Electricity

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...

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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...

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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...

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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...

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Explain the following.
a. Why is the tungsten used almost exclusively for filament of electric lamps?
b. Why are the conductors of electric heating devices, such as bread-toasters and electric irons, made of an alloy rather than a pure metal?
c. Why is the series arrangement not used for domestic circuits?
d. How does the resistance of a wire vary with its area of cross-section?
e. Why copper and aluminium wires are usually employed for electricity transmission?

a. Tungsten has a high resistance and melting point. It doesn't burn easily when heated because of its characteristic. Electric bulbs generate a lot of heat. As a result, tungsten is a popular metal...

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An electric lamp of 100 Ω, a toaster of resistance 50 Ω, and a water filter of resistance 500 Ω are connected in parallel to a 220 V source. What is the resistance of an electric iron connected to the same source that takes as much current as all three appliances, and what is the current through it?

A circuit diagram may be used to demonstrate the electric lamp, toaster, and water filter linked in parallel to a 220 V source: The resistors' equivalent resistance may be computed as follows:...

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