Answer: The relationship between potential difference and current is described by Ohm's law.
Q12. Fill in the following blanks with a suitable word: Ohm’s law states a relation between potential difference and ……
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Lakhmir Singh
. Thermodynamics essentially manages (I) interrelation of different types of energy and their change from one structure to another. (ii) energy changes in the cycles which rely just upon starting and last conditions of the minute frameworks containing a couple of particles. (iii) how and at what rate these energy changes are done. (iv) the framework in harmony state or moving from one balance state to another harmony state.
solution: Alternative (I) and (iv) are the appropriate responses. Thermodynamics manages interrelation of different types of energy and their change into one another. It additionally manages...
An electric bulb is rated at 220V, 100W. What is its resistance?
Answer: It is given in the question, V = 220V P = 100W R = ? We know that, R = V2/P R = 484 ohm
. Which of coming up next isn’t right? (I) ∆G is zero for a reversible response (ii) ∆G is positive for an unconstrained response (iii) ∆G is negative for an unconstrained response (iv) ∆G is positive for a non-unconstrained response
solution: Alternative (ii) is the appropriate response. ∆G gives a basis for suddenness at consistent strain and temperature. (I) If ∆G is negative (< 0). the cycle is...
Name the commercial unit of electric energy.
Answer: The kilowatt-hour is the commercial unit of electric energy.
Show how two 4 ohm resistors are connected to generate a total resistance of a) 2 ohms b) a resistance of 8 ohms
Answer: a) If you join them in parallel, 1R = 14 + 14 = 2/4 = 1/2 As a result, R = 2 ohm. b) By joining them in a sequence, R = 4 + 4 = 8 As a result, R = 8 ohm.
. Enthalpy of sublimation of a substance is equivalent to (I) enthalpy of combination + enthalpy of vapourisation (ii) enthalpy of combination (iii) enthalpy of vapourisation (iv) double the enthalpy of vapourisation
solution: Choice (I) is the appropriate response. Enthalpy of sublimation of a substance is equivalent to enthalpy of combination + enthalpy of vapourisation. Sublimation is immediate...
What are the various results of merging two resistances, one of value 2 ohm and the other of value 6 ohm?
Answer: given R1 = 2 Ohm R2 = 6 Ohm Let case 1 be parallel combination 1/R = 1/R1 + 1/R2 1/R = ½ + 1/6 = 4/6 R = 6/4 = 1.5 ohm Let case 2 be series combination R = R1 + R2 = 2+6 = 8...
Which type of circuit, series or parallel, is preferred while connecting a large number of bulbs: a) for decorating a hotel building from outside? b) for lighting inside the rooms of the hotel?
Answer: When the following type of circuit is used: a) The exterior of the hotel will be decorated in a series manner. The exterior lights do not need the same voltage difference b) lighting the...
The enthalpies of components in their standard states are taken as nothing. The enthalpy of arrangement of a compound (I) is consistently negative (ii) is consistently sure (iii) possibly certain or negative (iv) is rarely negative
solution: Choice (iii) is the appropriate response. Warmth of arrangement of a compound might be positive or negative.
Q11. A current of 5 amperes flows through a wire whose ends are at a potential difference of 3 volts. Calculate the resistance of the wire.
Answer: Given in question : Current, I = 5A Potential difference, V = 3V We know that, V = IR Therefore, 3 = 5 × R R = 3/5 = 0.6 Ohms
Which one has a higher electrical resistance: a 100 watt bulb or a 60 watt bulb?
Answer: Because we know that power is inversely related to resistance, a 60 watt bulb has a larger electrical resistance than a 100 watt bulb.
Two resistances, X and Y, are connected in series and parallel, respectively. Which means that the combined resistance will be lower than either of the separate resistances?
Answer: The resultant resistance will be less than either of the individual resistances when the two resistances X and Y are coupled in parallel.
Q10. A resistance of 20 ohms has a current of 2 amperes flowing in it. What potential difference is there between its ends?
Answer: Given in question : Resistance, R = 20 Ohms Current, I = 2 amp We know that, V = IR Therefore, V = 2 × 20 = 40V
How should the two 2 ohm resistances be put together to form a 1 ohm equivalent resistance?
Answer: The two resistances of 2 ohms must be connected in parallel to produce an equivalent resistance of 1 ohm.
Q9. A potential difference of 20V is applied across the ends of a resistance of 5 ohms. What current will flow in the resistance?
Answer: Given in question : Potential difference, V = 20V Resistance, R = 5 Ohms Current, I = ? We know that, V = IR 20 = I × 5 I = 20/5 = 4A
What will the overall resistance be if three 3 ohm resistances are connected in parallel?
Answer: Given, R1 = R2 = R3 = 3Ω 1/R = 1/R1 + 1/R2 + 1/R3 = 1/3 + 1/3 + 1/3 = 3/3 = 1 Therefore, R = 1Ω
What happens to the other bulbs in a parallel circuit if one bulb blows off?
Answer: When the bulbs are connected in a parallel configuration, they continue to glow. This occurs because the electricity flow is not disrupted, and the voltage differential between the other...
State two factors on which the electrical energy consumed by an electrical appliance depends.
Answer: The electrical energy required by an electrical equipment is determined by the following two factors: a) The appliance's usage time b) The appliance's power rating
Q8. Keeping the potential difference constant, the resistance of a circuit is halved. By how much does the current change?
Answer: Given in question : Potential difference = constant Also, we know that, V = IR I = V/R Given that V is constant, therefore, I will be proportional to 1/R. Therefore, when R is halved, I also...
In parallel, state the law of resistance combination.
Answer: The reciprocal of the combined resistance of a number of parallel resistances is equal to the total of the reciprocals of all the individual resistances, according to the law of parallel...
Q7. Which has less electrical resistance: a thin wire or a thick wire of the same length and same material?
Answer: Because the number of electrons present in the thick wire is more than that of the thin wire, a thick wire of the same length and substance will have less electrical resistance.
. Consider the responses given beneath. Based on these responses discover which of the arithmetical relations given in choices (I) to (iv) is right? ![\[\begin{array}{*{35}{l}} \left( a \right)\text{ }C\text{ }\left( g \right)\text{ }+\text{ }4\text{ }H\text{ }\left( g \right)\text{ }\to \text{ }CH4\text{ }\left( g \right);\text{ }rH\text{ }=\text{ }x\text{ }kJ\text{ }mol1 \\ ~ \\ \left( b \right)\text{ }C\text{ }\left( graphite,s \right)\text{ }+\text{ }2H2\text{ }\left( g \right)\text{ }\to \text{ }CH4\text{ }\left( g \right);\text{ }rH\text{ }=\text{ }y\text{ }kJ\text{ }mol1 \\ ~ \\ \left( I \right)\text{ }x\text{ }=\text{ }y \\ ~ \\ \left( ii \right)\text{ }x\text{ }=\text{ }2y \\ ~ \\ \left( iii \right)\text{ }x\text{ }>\text{ }y \\ ~ \\ \left( iv \right)\text{ }x\text{ }<\text{ }y \\ ~ \\ \end{array}\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-81745156192de5b4c48715895f94ae78_l3.png "Rendered by QuickLaTeX.com")
solution: Choice (iii) is the appropriate response. x > y because same bonds are formed in reactions (i) and (ii) but bonds between reactant molecules are broken only in reaction...
What happens to the other bulbs in a series circuit if one bulb blows off?
Answer: All of the other bulbs stop glowing when the bulbs are joined in series. Because the electrical appliances work on a definite voltage difference and in the series combination, the voltage...
What will the resultant resistance be if five 0.2 ohm resistances are linked in series?
Answer: The cumulative resistance of any number of resistances connected in series equals the individual resistances, according to the law of series combination of resistances. R = R1 + R2 + R3 + R4...
Q6. State the factors on which the strength of electric current flowing in a given conductor depends.
Answer: The following are the factors that influence the strength of an electric current flowing through a conductor: a) The voltage (or potential difference) between the conductor's ends b) The...
Based on thermochemical conditions (a), (b) and (c), discover which of the logarithmic connections given in alternatives (I) to (iv) is right. ![\[\begin{array}{*{35}{l}} \left( a \right)\text{ }C\text{ }\left( graphite \right)\text{ }+\text{ }O2\text{ }\left( g \right)\text{ }\to \text{ }CO2\text{ }\left( g \right)\text{ };\text{ }rH\text{ }=\text{ }x\text{ }kJ\text{ }mol1 \\ ~ \\ \left( b \right)\text{ }C\text{ }\left( graphite \right)\text{ }+12\text{ }O2\text{ }\left( g \right)\text{ }\to \text{ }CO\text{ }\left( g \right)\text{ };\text{ }rH\text{ }=\text{ }y\text{ }kJ\text{ }mol1 \\ ~ \\ \left( c \right)\text{ }CO\text{ }\left( g \right)\text{ }+12\text{ }O2\text{ }\left( g \right)\text{ }\to \text{ }CO2\text{ }\left( g \right)\text{ };\text{ }rH\text{ }=\text{ }z\text{ }kJ\text{ }mol1 \\ ~ \\ \left( I \right)\text{ }z\text{ }=\text{ }x\text{ }+\text{ }y \\ ~ \\ \left( ii \right)\text{ }x\text{ }=\text{ }y\text{ }\text{ }z \\ ~ \\ \left( iii \right)\text{ }x\text{ }=\text{ }y\text{ }+\text{ }z \\ ~ \\ \left( iv \right)\text{ }y\text{ }=\text{ }2z\text{ }\text{ }x \\ \end{array}\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-b40f2fc005f6abbd16305bc1f8b64ffb_l3.png "Rendered by QuickLaTeX.com")
solution: Choice (iii) is the appropriate response. \[\begin{array}{*{35}{l}} \left( a \right)\text{ }C\text{ }\left( graphite \right)\text{ }+\text{ }O2\text{ }\left( g \right)\text{ }\to...
Are the lights in your house wires in series?
Answer: In our homes, the lights are not connected in a series. They are linked in a parallel manner. The home's electric appliances are connected in parallel combinations to achieve the same...
Q5. Keeping the resistance constant, the potential difference applied across the ends of a component is halved. By how much does the current change?
Answer: Given in question : Resistance = constant We know that V = IR When resistance, R is constant, V is proportional to I Therefore, when V is halved, I also becomes half.
Give the law of series resistance combination.
Answer: According to the law of series combination of resistances, the combined resistance of any number of resistances connected in series equals the individual resistances.
Q4. What is the general name of the substances having infinitely high electrical resistance?
Answer: Insulators are materials with an infinitely high electrical resistance.
Q3. Name the physical quantity whose unit is “ohm”.
Electric resistance is a physical quantity with an ohm unit.
The entropy change can be determined by utilizing the articulation ![\[S\text{ }=\text{ }qrev/T\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-6bfe39a02f4a03c24c6a8eb9d86768e8_l3.png "Rendered by QuickLaTeX.com")
At the point when water freezes in a glass container, pick the right assertion among the accompanying : (I) ∆S (framework) diminishes however ∆S (environmental factors) stays as before. (ii) ∆S (framework) increments yet ∆S (environmental elements) diminishes. (iii) ∆S (framework) diminishes yet ∆S (environmental elements) increments. (iv) ∆S (framework) diminishes and ∆S (environmental factors) likewise diminishes.
solution: Alternative (iii) is the appropriate response. During the method involved with freezing energy is released,which is consumed by the environmental factors. Therefore,the entropy off...
Q2. Name the unit of electrical resistance and give its symbol.
Electrical resistance is measured in Ohms. The ohm symbol is as follows:Ω
Which electric heating devices in your home do you think have resistors which control the flow of electricity?
Answer The electric heating devices with resistors that control the flow of electricity are as follows: a) Iron (electric) c) Heater for the room c) Thermostat d) Oven (electric)
An electric iron is connected to the mains power supply of 220V. When the electric iron is adjusted at ‘minimum heating’ it consumes a power of 360W but at ‘maximum heating’ it takes a power of 840W. Calculate the current and resistance in each case.
Answer Given, 220 volts 360W = Pmin 840 W (Pmax) When the heat is turned down to a bare minimum, VI = Pmin I220 = 360 1.63 amps I V/I = R R = 1.63/1.63/1.63/1.63/1.63/1.63 134.96 ohms R = 134.96...
Two exactly similar heating resistances are connected in series and in parallel in two different circuits one by one. If the same current is passed through both the combinations, is more heat obtained per minute when they are connected in series or when they are connected in parallel? Give reason for your answer.
Answer More heat is obtained each minute when the heating resistances are connected in series. This is due to the fact that the overall resistance in a series configuration is higher than the total...
Name the law which relates the current in a conductor to the potential difference across its ends.
Ohm's law is a law that connects the current in a conductor to the potential difference between its ends. The conductor is the type of metal which allows the electrical current to flow through it.
a) How does the wire in the filament of a light bulb behave differently to the other wires in the circuit when the current flows? b) What property of the filament wire accounts for this difference?
Answer a) The behaviour of the filament wire in a light bulb differs from the behaviour of the other wires in the circuit, since the filament wire becomes white hot while the other wires do not. b)...
In an adiabatic interaction, no exchange of warmth happens among framework and environmental elements. Pick the right choice with the expectation of complimentary extension of an optimal gas under adiabatic condition from the accompanying. ![\[\begin{array}{*{35}{l}} \left( I \right)\text{ }q\text{ }=\text{ }0,\text{ }T\text{ }\ne \text{ }0,\text{ }w\text{ }=\text{ }0 \\ ~ \\ \left( ii \right)\text{ }q\text{ }\ne \text{ }0,\text{ }T\text{ }=\text{ }0,\text{ }w\text{ }=\text{ }0 \\ ~ \\ \left( iii \right)\text{ }q\text{ }=\text{ }0,\text{ }T\text{ }=\text{ }0,\text{ }w\text{ }=\text{ }0 \\ ~ \\ \left( iv \right)\text{ }q\text{ }=\text{ }0,\text{ }T\text{ }<\text{ }0,\text{ }w\text{ }\ne \text{ }0 \\ \end{array}\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-f414484974ac2116baf9c7e280488609_l3.png "Rendered by QuickLaTeX.com")
solution: Choice (iii) is the appropriate response. With the expectation of complimentary extension w = 0 For adiabatic cycle q = 0 From first law of thermodynamics, ...
The electrical resistivities of four materials P, Q, R, and S are given below: P: 6.84 × 10-8Ωm Q: 1.70 × 10-8Ωm R: 1.0 × 1015Ωm S: 11.0 × 10-7Ωm Which material will you use for making: a) heating element of electric iron b) connecting wires of electric iron c) covering of connecting wires Give reason for your choice in each case.
Answer a) An electric iron's heating element is S, which has a high resistance. This is a nichrome substance. b) An electric iron's connecting wires are Q because they have a low resistance. Copper...
If 20C of charge pass a point in a circuit in 1s, what current is flowing?
Answer: Given the information in the question: Charge moved, Q = 20C Time is taken, t = 1s To find, Current, I We know that the current is calculated as follows: I = Q/t We get by substituting the...
If the current flowing through a fixed resistor is halved, the heat produced in it will becomes: a) double b) one-half c) one-fourth d) four times
Answer c) four times is the correct answer. When the current flowing through a fixed resistor is cut in half, the heat generated in the resistor increases to four times its original value.
. ∆fUᶱ of arrangement of CH4 (g) at certain temperature is – 393 kJ mol–1. The worth of ∆ fHᶱ is (I) zero (ii) < ∆f Uᶱ (iii) > ∆f Uᶱ (iv) equivalent to ∆f Uᶱ
solution: Choice (ii) is the appropriate response.
Which of the following is the most likely temperature of the filament of an electric light bulb when it is working on the normal 220V supply line? a) 500°C b) 1500°C c) 2500°C d) 4500°C
Answer b) 2500°C is the correct answer.
In a filament types light bulb, most of the electric power consumed appears as: a) visible light b) infrared rays c) ultraviolet rays d) fluorescent light
Answer B) infrared rays is the right answer. Infrared rays are produced by the electric power consumed by a filament type light bulb.
Which of the following characteristics is not suitable for a fuse wire? a) thin and short b) thick and short c) low melting point d) higher resistance than rest of wiring
Answer b) thick and short is the correct answer. When a fuse wire is thick, there are more electrons available, which is not a desirable feature of a fuse wire.
During complete burning of one mole of butane, 2658 kJ of warmth is delivered. The thermochemical response for above change is ![\[\begin{array}{*{35}{l}} \left( I \right)\text{ }2C4H10\left( g \right)\text{ }+\text{ }13O2\left( g \right)\text{ }\to \text{ }8CO2\left( g \right)\text{ }+\text{ }10H2O\left( l \right)\text{ }cH\text{ }=\text{ }\text{ }2658.0\text{ }kJ\text{ }mol1 \\ ~ \\ \left( ii \right)\text{ }C4H10\left( g \right)\text{ }+13/2\text{ }O2\text{ }\left( g \right)\text{ }\to \text{ }4CO2\text{ }\left( g \right)\text{ }+\text{ }5H2O\text{ }\left( g \right)\text{ }cH\text{ }=\text{ }\text{ }1329.0\text{ }kJ\text{ }mol1 \\ ~ \\ \left( iii \right)\text{ }C4H10\left( g \right)\text{ }+13/2\text{ }O2\text{ }\left( g \right)\text{ }\to \text{ }4CO2\text{ }\left( g \right)\text{ }+\text{ }5H2O\text{ }\left( l \right)\text{ }cH\text{ }=\text{ }\text{ }2658.0\text{ }kJ\text{ }mol1 \\ ~ \\ \left( iv \right)\text{ }C4H10\text{ }\left( g \right)\text{ }+13/2\text{ }O2\text{ }\left( g \right)\text{ }\to \text{ }4CO2\text{ }\left( g \right)\text{ }+\text{ }5H2O\text{ }\left( l \right)\text{ }cH\text{ }=\text{ }+2658.0\text{ }kJ\text{ }mol1 \\ \end{array}\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-77b9f5a9cfe475e02540c7538497ae67_l3.png "Rendered by QuickLaTeX.com")
solution: Choice (iii) is the appropriate response. Exothermic reaction for combustion of one mole of butane is represented as \[\left( iii \right)\text{ }C4H10\left( g \right)\text{...
The heat produced in a wire of resistance ‘x’ when a current ‘y’ flows through it in time ‘z’ is given by: a) x2 × y × z b) x × z × y2 c) y × z2 × x d) y × z × x
Answer b) x z y2 is the correct answer.
The elements of electric heating devices are usually made of: a) tungsten b) bronze c) nichrome d) argon
Answer c) nichrome is the correct answer. Nichrome is used to make the components of electric heating equipment.
An electric fuse works on the: a) chemical effect of current b) magnetic effect of current c) lighting effect of current d) heating effect of current
Answer The correct answer is d) present heating impact. The working principle of an electric fuse is the heating effect of current.
The current passing through an electric kettle has been doubled. The heat produced will becomes: a) half b) double c) four times d) one-fourth
Answer c) four times is the correct answer. When the current in an electric kettle is doubled, the heat produced increases by four times.
. The volume of gas is decreased to half from its unique volume. The particular warmth will be ______. (I) decrease to half (ii) be multiplied (iii) stay consistent (iv) increment multiple times
solution: Alternative (iii) is the appropriate response. The particular warmth of a substance is the warmth needed to raise the temperature of 1 gram of a substance by one degree (1 K or 1...
The heat produced by passing an electric current through a fixed resistor is proportional to the square of: a) magnitude of resistance of the resistor b) temperature of the resistor c) magnitude of current d) time for which current is passed
Answer The correct answer is c) present magnitude. The heat generated by an electric current travelling through a fixed resistor is proportional to the square of the current magnitude.
a) Derive the expression for the heat produced due to a current I flowing for a time interval t through a resistor R having a potential difference V across its ends. With which name is this relation known? b) How much heat will an instrument of 12W produce in one minute if it is connected to a battery of 12V? c) The current passing through a room heater has been halved. What will happen to the heat produced by it? d) What is meant by the heating effect of current? Give two applications of the heating effect of current. e) Name the material which is used for making the filaments of an electric bulb.
Answer a) The amount of work done when an electric charge Q moves against a potential difference V is: W = Q V = W = Q V = W = Q V = W = Q V (1) We all know that current I = Q/T. IT = Q (2)...
The condition of a gas can be portrayed by citing the relationship between___. (I) pressure, volume, temperature (ii) temperature, sum, pressure (iii) the sum, volume, temperature (iv) pressure, volume, temperature, sum
solution: Alternative (iv) is the appropriate response. Condition of a framework can be portrayed by state capacities or state factors which are pressure, volume, temperature and measure of...
Which of the accompanying assertions is right? (I) The presence of responding species in a covered measuring utencil is an illustration of an open framework. (ii) There is a trade of energy just as a matter between the framework also, the environmental elements in a shut framework. (iii) The presence of reactants in a shut vessel made down of copper is an illustration of a shut framework. (iv) The presence of reactants in a canteen jar or some other shut protected vessel is an illustration of a shut framework.
solution: Alternative (iii) is the appropriate response. For a shut vessel made down of copper, regardless of can be traded between the framework and the environmental elements however energy trade...
Name the unit of electrical resistance and give its symbol.
Answer: An object's electrical resistance is a measure of its resistance to the flow of electric current. Electrical resistance is measured in Ohms. The ohm symbol is as follows: Ω
100 joules of heat is produced per second in a 4ohm resistor. What is the potential difference across the resistor?
Answer Given, 100J = H T = 1 second 4 ohms R = 4 ohms R = 4 ohm We are aware of this. I2RT = H I2 x 4 x 1 = 100 I2 = 100/4 5 amps = I IR = V 5 x 4 = V V equals 20
A resistance of 25Ω is connected to a 12V battery. Calculate the heat energy in joules generated per minute
Answer Given, R equals 25 V Equals 12 volts T = 60 seconds ? = H IR = V I=12/25 I=0.48 amp We are aware of this. H=I^2 RT H=345.6J
An electric heater of resistance 8Ω takes a current of 15A from the mains supply line. Calculate the rate at which heat is developed in the heater.
Answer Given, 8 ohm R Equals 8 ohm R = 8 ohm 15 amps = I T = 1 second We are aware of this. I2RT = H 1800 J/s H
A heating coil has a resistance of 200Ω. At what rate will heat be produced in it when a current of 2.5A flows through it?
Answer Given, R = 200 ohms ohms ohms ohms 2.5 amps I T = 1 second We are aware of this. I2RT = H 1250 J/s H
Name the law which relates the current in a conductor to the potential difference across its ends.
Answer: Ohm's law is a law that connects the current in a conductor to the potential difference between its ends.
When a current of 4amp passes through a certain resistor for 10 minutes, 2.88 × 104 J of heat are produced. Calculate a) the power of the resistor b) the voltage across the resistor
Answer Given, 4 amps = I T = 10 minutes = 600 seconds 2.88 104 J H = 2.88 104 J H = 2.88 104 J H = 2.88 104 a) We are aware of this. I2RT = H 42600R = 28800R...
Explain why, the current that makes the heater element very hot, only slightly warms the connecting wires leading to the heater.
Answer Because of their low resistance, the connecting wires leading to the heater are somewhat warmer than the wires that heat the heater element. This results in a flow of minimal heat generation...
Explain why, tungsten is used for making the filaments of an electric bulb.
Answer Because tungsten has an extremely high melting point, it is utilised to make electric bulb filaments. This means that the filament will continue to burn hot but will not melt. Tungsten is...
Why is an electric bulb not filled with air? Explain why argon or nitrogen is filled in an electric bulb.
Answer Because an electric bulb's filament is comprised of tungsten, which would quickly burn if it came into touch with oxygen in the air, it is not filled with air. Unreactive gases like argon and...
State three factors on which the heat produced by an electric current depends. How does it depend on these factors?
Answer The three elements that influence the amount of heat created by an electric current are as follows: a) The amount of heat produced is proportional to the square of the current. b) The amount...
Q10. a) Write down the formula for the heat produced when a current I is passed through a resistor R for time t. b) An electric iron of resistance 20 ohms draws a current of 5 amperes. Calculate the heat produced in 30 seconds.
Answer a) The following is the formula for calculating the amount of heat produced: I2Rt = H b) Assumed R equals 20 5 amps = I t = 30 seconds We are aware of this. I2Rt = H We know H = 15000J by...
Why does the connecting cord of an electric heater not glow hot while the heating element does?
Answer Electrical resistivity is a measurement of how well a substance resists the passage of electricity, whereas conductivity is a measure of how easily electricity flows. The heater's heating...
Explain why, filament type electric bulbs are not power efficient.
Answer Filament-type electric bulbs are inefficient because they waste the majority of their electricity as heat, with only a small portion converted to light.
Name two gases which are filled in filament type electric light bulbs.
Answer The two gases that are used to fill filament type electric light bulbs are as follows: Argon (a) Nitrogen (b)
Name two devices which work on the heating effect of electric current.
Answer The two devices that work on the heating effect of an electric current are as follows: a) An electric space warmer b) Fuse (electric)
Which effect of current is utilized in the working of an electric fuse?
Answer An electric fuse works by utilising the heating impact of current.
Which effect of current is utilized in an electric light bulb?
Answer An electric light bulb makes use of the current's heating effect.
Name two effects produced by electric current.
Answer The two impacts of electric current are as follows: a) Effect of heating b) Magnetic attraction
If the current passing through a conductor is doubled, what will be the change in heat produced?
Answer When the current going through a conductor is doubled, the amount of heat produced quadruples. This is due to the fact that the amount of heat produced is proportional to the square of the...
How does the heat H produced by a current passing through a fixed resistance wire depend on the magnitude of current I?
Answer: The amount of heat created by a current flowing through a fixed resistance wire is exactly proportional to the amount of current I flowing through the wire.
What do the following symbols mean in circuit diagrams?
Answer: a) In the circuit schematic, the symbol above denotes variable resistance. b) In the circuit schematic, the symbol above represents a closed plug key.
Compare how an ammeter and a voltmeter are connected in a circuit?
Answer: The ammeter is connected in series in an electric circuit, while the voltmeter is connected in parallel.
Which of the two is connected in series: ammeter or voltmeter?
Answer: The ammeter is linked in series with the voltmeter in place of the ammeter.
a) How many milliamperes are there in 1 ampere? b) How many microamperes are there in 1 ampere?
Answer: a)This table shows how many milliamperes there are in a single ampere: 1 amp = 103 milliamp b) The following is of the microamperes that are contained inside one ampere: 1 amp = 106 micro...
What is the unit of electric current?
Answer: The unit of electric current is ampere. Current is denied when the rate at which charge flows through the conductor is less than a certain threshold.
Which of the following equations shows the correct relationship between electrical units? 1A = 1C/s or 1C = 1A/s
Answer: The correct is 1A = 1C/s Current is denied when the rate at which charge flows through the conductor is less than a certain threshold. As a result, the right relationship is I=q/t, where q...
a) In which direction does conventional current flow around a circuit? b) In which direction do electrons flow?
Answer: a) Traditional current is carried from the positive terminal of the batter to its negative terminal in the outer circuit. b) In a battery, electrons move from the negative terminal to the...
Which particles constitute the electric current in a metallic conductor?
Answer: An electric current in a metallic conductor is made up of electrons, which are the particles that make up the current.
What actually travels through the wires when you switch on a light?
Answer: When the light is turned on, there is an increase in the flow of electrons across the wires.
What is the flow of charge called?
Answer: Electric current is the term used to describe the passage of charge. A conductor's electric current can be defined as the rate at which negative charges flow through it. Alternately, it can...
By what name is the physical quantity coulomb/second called?
Answer: The physical quantity coulomb/second is referred to as the ampere in the scientific community. It is defined as the elementary charge e, which has a value of 1.602 × 10-19 and is expressed...
The atoms of copper contain electrons and the atoms of rubber also contain electrons. Then why does copper conduct electricity but the rubber does not conduct electricity?
Answer: Copper atoms possess electrons, as do rubber atoms, however copper conducts electricity while rubber does not because copper contains unbound electrons held loosely together by the nucleus...
Three 2V cells are connected in series and used as battery in a circuit. a) What is the p.d at the terminals of the battery? b) How many joules of electric energy does 1C gain on passing through one cell and all the three cells?
Answer: a) As an example, if three cells, each having a voltage of 2 volts, are connected in series for the purpose of building a battery, the total potential difference between the terminals of the...
One coulomb charge is equivalent to the charge obtained in: a) 
electrons b) 
electrons c) 
electrons d) 
electrons
Answer: The correct option is d) 6.25×1018 electrons There are 6.25×1018 electrons in a one-coulomb charge. A coulomb is a charge carried by an ampere per the second current. 1C=1A * 1s We know...
The unit for measuring potential difference is: a) Watt b) Ohm c) Volt d) kWh
Answer: It is c) Volt that is the correct answer. For measuring the potential difference, the volt is the unit of measurement.
Which of the following units could be used to measure electric charge? a) Ampere b) Joule c) Volt d) Coulomb
Answer: The correct choice is d) Coulomb's law. Coulomb is a unit of measurement for electric charge that is used in science.
The device used for measuring potential difference is known as: a) Potentiometer b) Ammeter c) Galvanometer d) Voltmeter
Answer: It is d) Voltmeter that is the correct answer. A voltmeter is a gadget that is used to measure the difference between two potentials.
The work done in moving a unit charge across two points in an electric circuit is a measure of: a) Current b) Potential difference c) Resistance d) Power
Answer: It is b) Potential difference that is the correct answer. The potential difference between two places in an electric circuit is a measure of the amount of work required to move a unit charge...
e) State whether a voltmeter has a high resistance or a low resistance. Give reason for your answer.
Answer: In order to function, the resistance of the voltmeter must be high since it must draw only a small amount of current from an electric circuit.
c) What is the potential difference between the terminals of a battery if 250 joules of work is required to transfer 20 coulombs of charge from one terminal of battery to the other?
d) What is a voltmeter? How is a voltmeter connected in the circuit to measure the potential difference between two points. Explain with the help of a diagram.
c) Given, Work done = 250J Charge moved = 20C To find Potential difference We know that potential difference is given as Potential difference = (Work done)/(Charge moved) p.d = (250)/(20) = 12.5...
a) What do you understand by the term “potential difference”? b) What is meant by saying that the potential difference between two points is 1 volt?
Answer: a) The potential difference between two points is defined as the amount of work required to move a unit positive charge from one point to the other point. b) A 1-volt difference in potential...
a) Name a device that helps to measure the potential difference across a conductor. b) How much energy is transferred by a 12V power supply to each coulomb of charge which it moves around a circuit?
Answer: a) Voltmeter: a device that helps to measure the potential difference across a conductor. b) Given in question: Potential difference = 12V Charge moved = 1C To find, Work done We know that...
a) State the relation between potential difference, work done, and charge moved. b) Calculate the work done in moving a charge of 4 Coulomb from a point at 220 Volts to another point at 230 Volt.
Answer: a) The relation between potential difference, work done, and charge moved: Potential difference = (Work done)/(Charge moved) b) Given information in question: V1 = 220V V2 = 230V Charge...
What do you understand by the term “electric potential” at a point? What is the unit of electric potential?
Answer: The electric potential at a given point is defined as the amount of work required to move a unit positive charge from infinity to a specific point in space. The unit of electric potential is...
Which of the following are conductors and which are insulators? Sulphur, silver, copper, cotton, aluminium, air, nichrome, graphite, paper, porcelain, mercury, mica, Bakelite, polythene, manganin
Answer: Conductors are defined as the materials that allow an electric current to flow across their surfaces. Almost all metals are examples of conductors, including gold and silver. Insulators are...
What is meant by conductors and insulators? Give two examples of conductors and two of insulators.
Answer: Conductors are defined as the materials that allow electric current to flow across their surfaces. Almost all metals are examples of conductors, including gold and silver. The following are...
Fill in the following blanks with suitable words: a) Potential difference is measured in …………… by using a ……….. placed in …………… across a component. b) Copper is a good ……….. plastic is an …………….
Answer: a) Volts, voltmeter, parallel b) Conductor, insulator
Define one coulomb charge.
Answer: A coulomb is the amount of charge produced by a one-ampere current flowing for one second.
From a uniform disc of radius 
, a circular hole of radius 
is cut out. The centre of the hole is at 
from the centre of the original disc. Locate the centre of gravity of the resulting flat body
Let the unit area of the original disc be $\sigma$ The radius of the original disc is given as $2r$ Mass of the original disc can be calculated as $m=\pi\left(2 r^{2}\right) \sigma=4 \pi r^{2}...
A rope of negligible mass is wound around a hollow cylinder of mass 
and radius 40 cm. What is the angular acceleration of the cylinder if the rope is pulled with a force of 30 N? What is the linear acceleration of the rope? Assume that there is no slipping.
Mass of the hollow cylinder is given as $m=3 \mathrm{~kg}$ Radius of the hollow cylinder is given as $r=40 \mathrm{~cm}=0.4 \mathrm{~m}$ So, force applied will be $F=30 \mathrm{~N}$ Calculating the...
(a) A child stands at the centre of a turntable with his two arms outstretched. The turntable is set rotating with an angular speed of 
. How much is the angular speed of the child if he folds his hands back and thereby reduces his moment of inertia to 
times the initial value? Assume that the turntable rotates without friction
(b) Show that the child’s new kinetic energy of rotation is more than the initial kinetic energy of rotation. How do you account for this increase in kinetic energy?
(a) Initial angular velocity, is given as $\omega_{1}=40 \mathrm{rev} / \mathrm{min}$ Suppose the final angular velocity be $\omega_{2}$ Let the moment of inertia of the boy with stretched hands be...
A solid cylinder of mass 
rotates about its axis with angular speed 
. The radius of the cylinder is 
. What is the kinetic energy associated with the rotation of the cylinder? What is the magnitude of angular momentum of the cylinder about its axis?
Mass of the cylinder is given as $m=20 \mathrm{~kg}$ Angular speed is given as $\omega=100 \mathrm{rad} \mathrm{s}^{-1}$ Radius of the cylinder is given as $r=0.25 \mathrm{~m}$ So, the moment of...
(a) Find the moment of inertia of a sphere about a tangent to the sphere, given the moment of inertia of the sphere about any of its diameters to be 
, where 
is the mass of the sphere and is the radius of the sphere.
(b) Given the moment of inertia of a disc of mass M and radius about any of its diameters to be 
, find its moment of inertia about an axis normal to the disc and passing through a point on its edge.
The moment of inertia of a sphere about its diameter is $=2 \mathrm{MR}^{2} / 5$ and is also shown in the figure, As the the theorem of parallel axes says, M.I of a sphere about a tangent to the...
A 
irregular plank weighing 
is suspended in the manner shown below, by strings of negligible weight. If the strings make an angle of 
and 
respectively with the vertical, find the location of center of gravity of the plank from the left end.
Following is the FBD(Free Body Diagram) for the above figure: Length of the plank is given as $\mid=2 \mathrm{~m}$ $\theta_{1}=35^{\circ}$ and $\theta_{2}=55^{\circ}$ Let the tensions produced in...
Two particles, each of mass 
and speed v, travel in opposite directions along parallel lines separated by a distance 
. Show that the angular momentum vector of the two-particle system is the same whatever be the point about which the angular momentum is taken
Considering three points $Z, C$ and $X$ : Angular momentum at Z will be given as, $\mathrm{Lz}=\mathrm{mv} \times 0+\mathrm{mv} \times \mathrm{d}$ $=\mathrm{mvd}-(1)$ Angular momentum about $x$ will...
Show that 
is equal in magnitude to the volume of the parallelepiped formed on the three vectors, 
and 
.
Let the parallelepiped formed be: where, $\overrightarrow{O J}=\vec{a}, \overrightarrow{O L}=\vec{b}$ and $\overrightarrow{O K}=\vec{c}$ $\hat{n}$ is a unit vector along $\mathrm{OJ}$ and is...
A child sits stationary at one end of a long trolley moving uniformly with a speed 
on a smooth horizontal floor. If the child gets up and runs about on the trolley in any manner, what is the speed of the CM of the (trolley + child) system?
The child and the trolley are one system, and the youngster's movement within the cart is entirely internal. The velocity of the system's centre of mass will not change because there is no external...
A star 
times the mass of the sun and collapsed to a size of 12 km rotates with a speed of 
rev. per second. (Extremely compact stars of this kind are known as neutron stars. Certain stellar objects called pulsars belong to this category). Will an object placed on its equator remain stuck to its surface due to gravity? (mass of the sun 
).
If the outward centrifugal force is lesser than the inward gravitational pull, any matter will remain stuck to the surface. Gravitational force is given by the relation: $f_{G}=\frac{G M m}{R^{2}}$...
What is the unit of electric charge?
Answer: The unit of electric charge is the coulomb (coulomb). In electrical engineering, the term "coulomb" refers to the charge that is transferred with the help of a constant current of one ampere...
Two stars each of one solar mass 
are approaching each other for a headon collision. When they are a distance 
, their speeds are negligible. What is the speed with which they collide? The radius of each star is 
Assume the stars to remain undistorted until they collide. (Use the known value of G).
Mass of each star is given as $M=2 \times 10^{30} \mathrm{~kg}$ Radius of each star is given as $R=10^{4} \mathrm{~km}=10^{7} \mathrm{~m}$ Distance between the stars is given as $r=10^{9}...
How much work is done in moving a charge of 2C across two points having a potential difference of 12V?
Answer: Given, Potential difference = 12V Charge moved = 2C To find, Work done We know that the work done is given as Work done = p.d × charge moved = 12 × 2 = 24J So, to move a 2C charge with a 12V...
A rocket is fired vertically with a speed of 
from the earth’s surface. How far from the earth does the rocket go before returning to the earth? Mass of the earth 
; mean radius of the earth 
Velocity of the missile is given as $v=5 \times 10^{3} \mathrm{~m} / \mathrm{s}$ Mass of the Earth is known as $M_{E}=6 \times 10^{24} \mathrm{~kg}$ Radius of the Earth is given as $R_{E}=6.4 \times...
What is the SI unit of potential difference?
Answer: The SI unit of potential difference is volts. It is a potential difference that resists a resistance of one ohm through a current of one ampere.
How much work is done when one-coulomb charge moves against a potential difference of 1 volt?
Answer: Given the information in question: Potential difference = 1V Charge to be moved = 1C To find, Work done We know that the work done is given as: Work done = Potential difference × Charge...
What is meant by saying that the electric potential at a point is 1 volt?
Answer: In order to move one unit of positive charge from infinity to a specific point, the electric potential at that point must be one volt, which means that one joule of work must be done.
A body weighs 
on the surface of the earth. What is the gravitational force on it due to the earth at a height equal to half the radius of the earth?
Weight of the man is given as $W=63 \mathrm{~N}$ Acceleration due to gravity at height 'h' from the Earth's surface is: g'=g1+hRe2...
a) What do the letters p.d stand for? b) Which device is used to measure p.d?
Answer: a).) p.d. stand for potential difference b) voltmeter is a device which used to measure potential difference
How will you ‘weigh the sun’, that is estimate its mass? The mean orbital radius of the earth around the sun is 
.
Earth's orbit has a radius of $r=1.5 \times 10^{11} \mathrm{~m}$ Time taken by the Earth for one complete revolution can be $\mathrm{T}=1$ year $=365.25$ days i.e. $T=(365.25 \times 24 \times 60...
Choose the correct answer from among the given ones: the direction of the gravitational intensity at an arbitrary point 
is indicated by the arrow (i) 
, (ii) e, (iii) f, (iv) 
.
(ii) e Reason: From the previous response, we can deduce that, The gravitational intensity at P is directed downwards along 'e' using the logic/explanation
Which of the following statements correctly defines a volt? a) A volt is a joule per ampere b) A volt is a joule per coulomb
Answer: The joule/coulomb is also known as volt. The SI unit of electric potential is the volt. The potential difference between two points of a current-carrying wire of 1 ampere is represented by...
By what other name is the unit joule/coulomb called?
Answer: The joule/coulomb is also known as volt. The SI unit of electric potential is the volt. The potential difference between two points of a current-carrying wire of 1 ampere is represented by...
Which of the following symptoms is likely to afflict an astronaut in space
(a) headache,
(b) orientational problem.
(a). Astronauts may get headaches as a result of the increased blood supply to their faces. (b). Because space has multiple orientations, an astronaut may experience orientational issues.
Which of the following symptoms is likely to afflict an astronaut in space
(a) swollen feet,
(b) swollen face
(a) Because blood flow to the feet is not increased in zero gravity, the astronaut's feet do not swell. (b) There is more blood supply to the astronaut's face. As a result, the astronaut's face will...
A comet orbits the Sun in a highly elliptical orbit.
(a) potential energy
(b) total energy throughout its orbit? Neglect any mass loss of the comet when it comes very close to the Sun.
(a) Potential energy changes along the path. (b) Total energy will remain constant throughout the orbit.
A comet orbits a sun in a highly elliptical orbit. Does the comet have a constant
(a) linear speed,
(b) angular speed,
(c) angular momentum,
(d) kinetic energy,
(e) potential energy,
(f) total energy throughout its orbit? Neglect any mass loss of the comet when it comes very close to the sun.
A comet in an elliptical orbit around the Sun has constant angular momentum and total energy owing to the Law of Conservation of Energy at all locations, but other variables change. The torque...
Does the escape speed of a body from the earth depend on
(a) the direction of projection,
(b) the height of the location from where the body is launched?
The escape speed can be given by the relation, $v=\sqrt{\frac{2 G M}{R}}=\sqrt{2 g R}$ (a) The escape speed does not depend on the direction of projection of a body. (b) Because the escape velocity...
Choose the correct alternative:
(a) If the zero of potential energy is at infinity, the total energy of an orbiting satellite is negative of its kinetic/potential energy.
(b) The energy required to launch an orbiting satellite out of earth’s gravitational influence is more/less than the energy required to project a stationary object at the same height (as the satellite) out of earth’s influence.
(a) The total energy of an orbiting satellite is negative of its kinetic energy if the zero potential energy is at infinity. (b) The energy required to launch an orbiting satellite out of Earth's...
Let us assume that our galaxy consists of 
stars each of one solar mass. How long will a star at a distance of 
ly from the galactic centre take to complete one revolution? Take the diameter of the Milky Way to be 
.
Mass of our galaxy is given as $M=2.5 \times 10^{11}$ solar mass 1 Solar mass as we know is, Mass of Sun $=2 \times 10^{30} \mathrm{~kg}$ Mass of our galaxy as we know is $M=2.5 \times 10^{11}...
lo, one of the satellites of Jupiter, has an orbital period of 
days and the radius of the orbit is 
Show that the mass of J upiter is about one-thousandth that of the sun.
Orbital period of $I0$, is given as $T_{10}=1.769$ days $=1.769 \times 24 \times 60 \times 60 \mathrm{~s}$ Orbital radius of $I0$, is given as $R_{10}=4.22 \times 10^{8} \mathrm{~m}$ Mass of jupiter...
Suppose there existed a planet that went around the Sun twice as fast as the earth. What would be its orbital size as compared to that of the earth?
Time taken by the earth for one complete revolution is represented by $\mathrm{T}_{\mathrm{E}}$ having value $1$ Year Radius of Earth's orbit is represented by $\mathrm{R}_{\mathrm{E}}$ having value...
Choose the correct alternative:
(a) Acceleration due to gravity is independent of the mass of the earth/mass of the body.
(b) The formula 
is more/less accurate than the formula 
for the difference of potential energy between two points 
and 
distance away from the centre of the earth.
(a) Acceleration due to gravity is given by the formula: $g=G{{M}_{e}} /{{ {R}_{e}}^{2}}$ is Hence, it is independent of mass of body, but is dependent on mass of earth. (b) Gravitational...
Choose the correct alternative:
(a) Acceleration due to gravity increases/decreases with increasing altitude.
(b) Acceleration due to gravity increases/decreases with increasing depth (assume the earth to be a sphere of uniform density).
(a) According to the formula g′=g(1-R2h), acceleration decreases. where h is the height and R is the earth's radius (b) According to the formula g′=g(1−Rd),, acceleration decreases. where d is the...
Answer the following: If you compare the gravitational force on the earth due to the sun to that due to the moon, you would find that the Sun’s pull is greater than the moon’s pull. (you can check this yourself using the data available in the succeeding exercises). However, the tidal effect of the moon’s pull is greater than the tidal effect of the sun. Why?
Tidal effects are inversely proportional to the cube of distance, whereas gravitational force is inversely proportional to the square of distance. The moon will have a stronger influence on the...
Which of the following is the correct order of the size of the given species:
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Option (iv) is the answer. The size of an anion, cation, and neutral species for a given element is in this order: anion>element>cation. Because of its higher z-effective, cation has the...
The elements in which electrons are progressively filled in 4f-orbital are called
(i) actinoids
(ii) transition elements
(iii) lanthanoids
(iv) halogens
Option (iii) is the answer. In lanthanoids, the 4f orbital is gradually filled with electrons. Lanthanoids have a broad electrical configuration. [Xe]4f 1-145d0-16s2.
The period number in the long form of the periodic table is equal to
(i) magnetic quantum number of any element of the period.
(ii) an atomic number of any element of the period.
(iii) maximum Principal quantum number of any element of the period.
(iv) maximum Azimuthal quantum number of any element of the period.
Option (iii) is the answer. Period number = maximum n of any element where 'n' stands for the principle quantum number. It determines the element's period number. Mg, for example, has a maximum main...
Explain the following terms with one example each. (a) Corrosion (b) Rancidity
Answer: (a) Corrosion occurs when oxygen oxidizes a refined metal to generate oxides. During corrosion, the metal steadily deteriorates. Iron rusting is a type of corrosion that converts iron to...
Oil and Fat containing food items are flushed with Nitrogen. Why?
Answer: The primary goal of flushing Nitrogen into food packages that contain oil and fat items is to prevent rancidity, which occurs when the oil or fat reacts with oxygen, releasing an unpleasant...
Why do we apply paint on iron articles?
Answer: To keep iron goods from rusting, they are painted with a protective coating. When a metal surface is left unpainted, it comes into contact with the oxygen in the air and, in the presence of...
A shiny brown coloured element ‘X’ on heating in the air becomes black in colour. Name the element ‘X’ and the black coloured compound formed.
Answer: Copper is the metallic element with a gleaming brown sheen to it (Cu). When copper is heated in the presence of oxygen, copper oxide is formed as a result of the reaction with the oxygen in...
Explain the following in terms of gain of oxygen with two examples each. (a) Oxidation (b) Reduction
Answer: (a) When oxygen is added to an element to generate the element's respective oxide, the element being oxidised is the element being oxidised in the chemical reaction. Example: 4Na(s) + O2(g)...
What do you mean by a precipitation reaction? Explain by giving examples.
Answer: When two soluble salt solutions are mixed, the ions are exchanged between the compounds in a twofold displacement reaction. When one of these chemicals is solid (insoluble in water), it...
In the refining of Silver, the recovery of silver from Silver nitrate solution involves displacement reaction by Copper metal. Write down the reaction involved.
Answer: Cu(s) + 2AgNO3(aq) → Cu(NO3)2(aq) + 2Ag(s) Explanation: As the name implies, a displacement reaction involves the displacement of an atom by another atom. The general displacement response...
What is the difference between displacement and double displacement reactions? Write relevant equations for the above.
Answer: A displacement reaction occurs when a more reactive substance displaces a less reactive chemical from its salt solution, while a double displacement reaction occurs when two compounds...
Write one equation each for decomposition reactions in which energy is supplied in the form of heat, light or electricity. Solution:
Answer: a) Thermochemical decomposition (Thermolysis) Potassium chlorate decomposes into potassium chloride and oxygen when heated to high temperatures. This reaction produces oxygen. 2KClO3 + Heat...
Why are decomposition reactions called the opposite of Combination reactions? Write equations for decomposition reactions.
Answer: A combination process occurs when two or more molecules combine to produce a larger molecule, whereas a decomposition reaction occurs when larger molecules break into two or more smaller...
Why is respiration considered to be an exothermic reaction?
Answer: We need the energy to live. We get this energy from our food. During digestion, food molecules are broken down into simpler molecules like glucose. These molecules react with oxygen in our...
What is meant by exothermic and endothermic reactions? Give examples.
Answer: When energy is taken from the surrounding environment in the form of heat, an endothermic process takes place. (For example, photosynthesis, ice melting, and evaporation are all examples of...
Write a balanced chemical equation for the following and identify the type of reaction of each case
1. KBr + BaI2 → KI + BaBr2
2. ZnCO3 → ZnO + CO2
3. H2 + Cl → HCl
4. Mg + HCl → MgCl2 + H
Answer: When solving an equation for a chemical reaction, a balanced equation is one where the number of atoms for each element in the reaction, as well as the total charge, for both the reactants...
Write the balanced chemical equation for the following reactions.
1. Calcium hydroxide + Carbon dioxide —-> Calcium carbonate + Water
2. Zinc + Silver nitrate —-> Zinc nitrate + Silver
3. Aluminium + Copper chloride —-> Aluminium chloride + Copper
4. Barium chloride + Potassium sulphate —-> Barium sulphate + Potassium chloride
Answer: When solving an equation for a chemical reaction, a balanced equation is one where the number of atoms for each element in the reaction, as well as the total charge, for both the reactants...
Balance the following chemical equations.
(a) 
(b) 
(c) 
(d) 
Answer: When solving an equation for a chemical reaction, a balanced equation is one where the number of atoms for each element in the reaction, as well as the total charge, for both the reactants...
Which of the following is not an actinoid?
(i) Curium (Z = 96)
(ii) Californium (Z = 98)
(iii) Uranium (Z = 92)
(iv) Terbium (Z = 65)
Option (iv) is the answer. Any group of 15 elements in the periodic table, ranging from actinium to lawrencium (atomic numbers 89–103), is known as an actinoid element. As evident from the...
Translate the following statements into chemical equations and balance them. (c) Barium chloride reacts with aluminium sulphate to give Aluminium chloride and a precipitate of barium sulphate. (d) Potassium metal reacts with water to give potassium hydroxide and Hydrogen gas.
Answer: (c) Unbalanced: BaCl2 + Al2(SO4)3 → AlCl3 + BaSO4 Balanced: 3BaCl2 + Al2(SO4)3 → 2AlCl3 + 3BaSO4 (d) Unbalanced: K + H2O → KOH + H2 Balanced: 2K + 2H2O → 2KOH +...
Translate the following statements into chemical equations and balance them.
(a) Hydrogen gas combines with nitrogen to form ammonia.
(b) Hydrogen sulphide gas burns in air to give water and sulphur dioxide.
Answer: (a) Unbalanced: H2 + N2 → NH3 Balanced: 3H2 + N2 → 2NH3 (b) Unbalanced: H2S + O2 → H2O + SO2 Balanced: 2H2S + 3O2 → 2H2O + 2SO2
What is a balanced chemical equation? Why should a chemical equation be balanced?
Answer: When there are the same number of distinct atoms on both the reactant and product sides of an equation, it is said to be "balanced." It is required to have a balanced chemical equation in...
What happens when dilute hydrochloric acid is added to iron fillings? Tick the correct answer.
1. Hydrogen gas and Iron chloride are produced.
2. Chlorine gas and Iron hydroxide are produced.
3. No reaction takes place.
4. Iron salt and water are produced.
Answer: Option 1) is correct. An explanation is given below. The Chlorine from Hydrogen chloride is displaced by the Iron fillings, resulting in the subsequent reaction. 2HCl + Fe → FeCl2 +...
The above reaction is an example of a) Combination reaction. Double displacement reaction. Decomposition reaction. Displacement reaction.
Answer: Option d) This displacement of oxygen from the ferrous oxide to the aluminum metal forms Aluminium Oxide. Aluminum reacts faster than Fe in this reaction. So Al displaces Fe from its oxide....
Which of the statements about the reaction below are incorrect? 2PbO(s) + C(s) → 2Pb(s) + CO2(g)
(a) Lead is getting reduced
(b) Carbon Dioxide is getting oxidised
(c) Carbon is getting oxidised
(d) Lead oxide is getting reduced
(i) (a) and (b)
(ii) (a) and (c)
(iii) (a), (b) and (c)
(iv) all
Answer: With the aforementioned reaction, lead oxide (PbO) is reduced to lead and carbon (C) is oxidised to form carbon dioxide (CO2). As a result, both statements (a) and (b) are correct. As a...
Identify the substances that are oxidized and that are reduced in the following equation. i) 4Na(s) + 
(g) → 
(s) ii) CuO(s) + H2(g) → Cu(s) + H2O(l)
Answer: The chemical that has been oxidised is referred to as a reduction agent. The chemical that has been reduced is referred to as an oxidising agent. (i) 4Na(s) + O2(g) → 2Na2O(s) Oxidized...
Give an example of a double displacement reaction other than the one given in Activity 1.10.
Answer: Reaction It is possible to have a double displacement reaction between silver nitrate (AgNO3) and sodium chloride (NaCl) in certain circumstances. It is discovered that negative and positive...
Why does the colour of copper sulphate solution change when an iron nail is dipped in it?
Answer: A copper sulphate solution is formed when an iron nail is dipped in it, and the iron displaces the copper from the copper sulphate solution due to the fact that iron is more reactive than...
Why is the amount of gas collected in one of the test tubes in Activity 1.7 double of the amount collected in the other? Name this gas
Answer: In activity 1.7, the amount of gas collected in one of the test tubes is twice the amount collected in the other, due to the hydrolysis of water, which results in the release of H2 and O2...
A solution of a substance ‘X’ is used for whitewashing. (i) Name the substance ‘X’ and write its formula.
(ii) Write the reaction of the substance ‘X’ named in (i) above with water.
Answer: (i) The whitewashing solution is calcium oxide (CaO), often known as quicklime. Quicklime is used for whitewashing because it combines with water to form calcium hydroxide (CaOH) and absorbs...
Write a balanced chemical equation with state symbols for the following reactions
i) Solutions of Barium chloride and Sodium sulphate in water react to give insoluble Barium sulphate and solution of Sodium chloride.
ii) Sodium hydroxide solution in water reacts with hydrochloric acid solution to produce Sodium chloride solution and water.
Answer: A chemical equation represents a chemical process as a collection of substances. A balanced chemical equation has the same number of atoms on both sides of the equation. i) BaCl2 + Na2SO4 →...
Write a balanced equation for the following chemical reactions: iii) Sodium + Water —-> Sodium hydroxide + Hydrogen
Answer: A chemical equation represents a chemical process as a collection of substances. A balanced chemical equation has the same number of atoms on both sides of the equation. (iii) 2Na(s) + 2H2O...
Write a balanced equation for the following chemical reactions. i) Hydrogen + Chloride —-> Hydrogen chloride ii) Barium chloride + Aluminium sulphate —> Barium sulphate + Aluminium chloride
A chemical equation represents a chemical process as a collection of substances. A balanced chemical equation has the same number of atoms on both sides of the equation. (i) H2 (g) + Cl2 (g) → 2HCl...
The front face of a circular wire carrying current behaves like a north pole. The direction of current in this face of the circular wire is: a) clockwise b) downwards c) anticlockwise d) upwards
Answer: The correct option is c) anticlockwise The front face of the circular wire (or coil) is the South pole if the current flows clockwise around it (S-pole). The current flow in the circular...
The magnetic field lines in the middle of the current-carrying solenoid are: a) circles b) spirals c) parallel to the axis of the tube d) perpendicular to the axis of the tube
Answer: The correct option is c) parallel to the axis of the tube Explanation: The magnetic field lines inside a current-carrying solenoid are parallel to the tube's axis.
A soft iron bar is inserted inside a current-carrying solenoid. The magnetic field inside the solenoid: a) will decrease b) will increase c) will become zero d) will remain the same
Answer: The correct option is b) will increase Explanation: To boost the magnetic field within a current-carrying solenoid, insert a soft iron bar. The iron bar gains magnetic properties when...
The magnetic effect of current was discovered by: a) Maxwell b) Fleming c) Oersted d) Faraday
Answer: The correct option is c) Oersted Explanation: Hans Christian Oersted discovered the magnetic effect of electricity in 1820. He showed the effect by observing the deflection of a long...
The most suitable material for making the core of an electromagnet is: a) soft iron b) brass c) aluminum d) steel
Answer: The correct option is a) soft iron Explanation: When creating the core of an electromagnet, soft iron is preferred over hard iron because the core is employed in a solenoid to generate the...
If the direction of electric current in a solenoid when viewed from a particular end is anticlockwise, then this end of solenoid will be: a) west pole b) south pole c) north pole d) east pole
Answer: The correct option is c) north pole Explanation: Using the clock face rule, we found that if the flow of electric current in a solenoid is anticlockwise, that end is the north pole. Both a...
The direction of current in the coil at one end of an electromagnet is clockwise. This end of the electromagnet will be: a) north pole b) east pole c) south pole d) west pole
Answer: The correct option is c) south pole Explanation: An electromagnet is a current-carrying coil that might be regarded to be inductive. To determine which end of the electromagnet will behave...
The north-south polarities of an electromagnet can be found easily by using: a) Fleming’s right-hand rule b) Fleming’s left-hand rule c) Clock face rule d) Left-hand thumb rule
Answer: The correct option is c) Clock face rule Explanation: Option c is the best choice. This rule is more straightforward than other rules because it only requires that you glance at the coil...
Which of the following correctly describes the magnetic field near a long straight wore? a) the field consists of straight lines perpendicular to the wire b) the field consists of straight lines parallel to the wire c) the field consists of radial lines originating from the wire d) the field consists of concentric circles centered on the wire
Answer: The correct option is d) the field consists of concentric circles centered on the wire Explanation: In magnetism and electricity, a straight wire or conductor forms concentric magnetic...
The magnetic field inside a long straight solenoid carrying current: a) is zero b) decreases as we move towards its ends c) increases as we move towards its ends d) is the same at all points
Answer: option d) A long straight solenoid's magnetic field is constant. The magnetic field in the solenoid is constant since the lines are parallel.
The strength of the magnetic field between the poles of an electromagnet would be unchanged if: a) current in the electromagnet winding were doubled b) direction of current in electromagnet were reversed c) distance between the poles of electromagnet were doubled d) material of the core of electromagnet were changed
Answer: The correct option is b) direction of current in electromagnet were reversed. Answer: The electromagnetic winding's current direction is reversed only on one side of the pole. The magnetic...
The phenomenon of electromagnetic induction is: a) the process of charging a body b) the process of generating magnetic field due to a current passing through a coil c) producing induced current in a coil due to relative motion between a magnet and the coil d) the process of rotating a coil of an electric motor
Answer: The correct option is c) producing induced current in a coil due to relative motion between a magnet and the coil Explanation: According to Faraday's Law of electromagnetic induction, a...
A horizontal wire carries a current as shown in figure below between magnetic poles N and S: Is the direction of the force on the wire due to the magnet: a) in the direction of the current b) vertically downwards c) opposite to the current direction d) vertically upwards
Answer: The correct answer is d) vertically upwards Explanation: Using Fleming's left-hand rule, the wire's force acts vertically upward. The index finger indicates the direction of the magnetic...
A magnetic field exerts no force on: a) an electric charge moving perpendicular to its direction b) an unmagnetized iron bar c) a stationary electric charge d) a magnet
Answer: The correct option is c) a stationary electric charge Explanation: The magnetic field is the area around a magnet where the magnetic force is delivered. The magnetic field lines can be...
An electric motor is a device which transforms: a) mechanical energy to electrical energy b) heat energy to electrical energy c) electrical energy to heat energy only d) electrical energy to mechanical energy
Answer: The correct option is a) mechanical energy to electrical energy Explanation: A motor is a machine that turns electrical energy into mechanical energy. Electricity into mechanical energy in a...
A current flows in a wire running between the S and N poles of a magnet lying horizontally shown in the figure below:The force on the wire due to the magnet is directed: a) from N to S b) from S to N c) vertically downwards d) vertically upwards
Answer: The correct option is c) vertically downwards Explanation: Using Fleming's left-hand rule, the force on the wire should be vertical. The index finger indicates the direction of the magnetic...
The force exerted on a current-carrying wire placed in a magnetic field is zero when the angle between the wire and the direction of magnetic field is: a) 45⸰ b) 60⸰ c) 90⸰ d) 180⸰
Answer: The correct option is c) 180⸰ The wire is at an angle of 180° to the magnetic field. Force is felt by a current-carrying wire in a magnetic field. Using the formula F = BILsinθ ———–(1) where...
The force experienced by a current-carrying conductor placed in a magnetic field is the largest when the angle between the conductor and the magnetic field is: a) 45⸰ b) 60⸰ c) 90⸰ d) 180⸰
Answer: The correct option is c) 90⸰ Explanation: A current-carrying conductor feels the most force when the magnetic field and current are perpendiculars.
An electron beam enters a magnetic field at right angles to it as shown in the figure: The direction of force acting on the electron beam will be: a) to the left b) to the right c) into the page d) out of the page
Answer: The correct option is c) into the page Explanation: Using Fleming's left-hand rule, the electron beam will be forced into the paper. The index finger indicates the direction of the magnetic...
The frequency of alternating current supply in India is: a) 0 Hz b) 50 Hz c) 60 Hz d) 100 Hz
Answer: The correct option is b) 50 Hz Explanation: In India, only 220-250 volts and 50 Hz are allowed. Because the high frequency in India can completely heat up the electrical wire.
The frequency of direct current is: a) 0 Hz b) 50 Hz c) 60 Hz d) 100 Hz
Answer: The correct option is a) 0 Hz Explanation:The DC frequency is 0 since the current flow is unidirectional. Direct current (DC) has no chance of reversing direction, and its frequency is...
An induced current is produced when a magnet is moved into a coil. The magnitude of induced current does not depend on: a) the speed with which the magnet is moved b) the number of turns of the coil c) the resistivity of the wire of the coil d) the strength of the magnet
Answer: The correct option is b) Explanation: The induced emf is represented by: e=-NAd(B)dt e=-N A \frac{d(B)}{d t} Here, $N$ is the number of turns of the coil, $A$ is the area of the coil, and...
A d.c generator is based on the principle of: a) electrochemical induction b) electromagnetic induction c) magnetic effect of current d) heating effect of current
Answer: The correct option is b) electromagnetic induction Explanation: On the basis of electromagnetic induction, d.c. generators produce an electromotive force when the flux across the generator...
An electric generator converts: a) electrical energy into mechanical energy b) mechanical energy into heat energy c) electrical energy into chemical energy d) heating effect of current
Answer: The correct option is d) Explanation: Any equipment that turns mechanical energy into electricity for transmission and distribution to residential, commercial, and industrial clients....
The north pole of a long bar magnet was pushed slowly into a short solenoid connected to a galvanometer. The magnet was held stationary for a few seconds with the north pole in the middle of the solenoid and then withdrawn rapidly. The maximum deflection of the galvanometer was observed when the magnet was: a) moving towards the solenoid b) moving into solenoid c) at rest inside the solenoid d) moving out of the solenoid
Answer: The correct option is d) moving out of the solenoid Explanation: The galvanometer displays no deflection when the bar magnet is fixed. A galvanometer shows deflection when the north pole of...
Each one of the following changes will increase emf in a simple generator except: a) increasing the number of turns in the armature coil b) winding the coil on a soft iron armature c) increasing the size of the gap in which the armature turns d) increasing the speed of rotation
Answer: The correct option is c) increasing the size of the gap in which the armature turns