Solutions: The following is a graphical way for finding zeroes:- When solving any polynomial equation, the total number of zeroes equals the total number of times the curve meets the x-axis. i) The...
Two events and will be independent, if
(A) and are mutually exclusive
(B)
(C)
(D)
Solution: Answer: (B) $P\left(A^{\prime} B^{\prime}\right)=[1-P(A)][1-P(B)]$Concept: Two events are independent, statistically independent, or stochastically independent if the occurrence of one...
The probability of obtaining an even prime number on each die, when a pair of dice is rolled is
A. 0
B.
c.
D.
Solution: Answer: D. $1 / 36$ Explanation: Given A pair of dice is rolled. Hence the number of outcomes $=36$ The chance of getting an even prime number on each die is represented by the...
In a hostel, of the students read Hindi newspaper, read English newspaper and read both Hindi and English newspapers. A student is selected at random.
(a) Find the probability that she reads neither Hindi nor English newspapers.
(b) If she reads Hindi newspaper, find the probability that she reads English newspaper.
(c) If she reads English newspaper, find the probability that she reads Hindi newspaper
Given: The letters $H$ and $E$ stand for the number of students who read the Hindi newspaper and the English daily, respectively. Hence, $\mathrm{P}(\mathrm{H})=$ Probability of students who read...
Q.The following real numbers have decimal expansions as given below. In each case, decide whether they are rational or not. If they are rational, and of the form, p q what can you say about the prime factors of q?
(i) \[\mathbf{43}.\mathbf{123456789}\] (ii) \[\mathbf{0}.\mathbf{120120012000120000}\ldots \ldots \] $\left( III \right)$ $43.\overline{123456789}$ (i) \[\mathbf{43}.\mathbf{123456789}\] Since ,it...
One card is drawn at random from a well shuffled deck of 52 cards. In which of the following cases are the events and independent?
(i) E: ‘the card drawn is a spade’ F: ‘the card drawn is an ace’
(ii) E: ‘the card drawn is black’ : ‘the card drawn is a king’
(iii) E: ‘the card drawn is a king or queen’ F: ‘the card drawn is a queen or jack’.
Solution: Given: A deck of 52 cards. Concept: Two events are independent, statistically independent, or stochastically independent if the occurrence of one does not affect the probability of...
Probability of solving specific problem independently by and are and respectively. If both try to solve the problem independently, find the probability that (i) The problem is solved
(ii) Exactly one of them solves the problem.
Given, $P(A)=$ Probability of solving the problem by $A=1 / 2$ Concept: $\mathrm{P}(\mathrm{B})=$ Probability of solving the problem by $\mathrm{B}=1 / 3$ Because $A$ and $B$ both are...
Two balls are drawn at random with replacement from a box containing 10 black and 8 red balls. Find the probability that (i) both balls are red.
(ii) First ball is black and second is red.
(iii) One of them is black and other is red.
Solution: Given A box with ten black and eight red balls. Total number of balls in box = 18 (i) Both balls are red. Probability of getting a red ball in first draw $=8 / 18=4 / 9$ As the ball is...
A die is tossed thrice. Find the probability of getting an odd number at least once.
Given: A die is tossed three times. Then the sample space $S={1,2,3,4,5,6}$ Let $\mathrm{P}(\mathrm{A})=$ probability of getting an odd number in first throw. $\Rightarrow P(A)=3 / 6=1 / 2 .$ Let...
Events and are such that and not or . State whether and are independent?
Solution: Given: $P(A)=1 / 2, P(B)=7 / 12$ and $P($ not $A$ or $\operatorname{not} B)=1 / 4$Concept: Two events are independent, statistically independent, or stochastically independent if the...
If and are two events such that and , find not and not B).
Solution: Given $P(A)=1 / 4, P(B)=1 / 2$ and $P(A \cap B)=1 / 8$ Concept: $P($ not $A$ and $\operatorname{not} B)=P\left(A^{\prime} \cap B^{\prime}\right)$ As, $\left{A^{\prime} \cap B^{\prime}=(A...
Let and be independent events with and . Find (i)
(ii)
(iii)
(iv)
Solution: Given: $\mathrm{P}(\mathrm{A})=0.3$ and $\mathrm{P}(\mathrm{B})=0.4$ (i) $P(A \cap B)$Given $P ( A )=0.3$ and $P ( B )=0.4$ When A and B are independent.Two events are independent,...
Let and be independent events with and . Find (i)
(ii)
(iii)
(iv)
Given $P ( A )=0.3$ and $P ( B )=0.4$ (i) $P(A \cap B)$ When A and B are independent. Two events are independent, statistically independent, or stochastically independent if the occurrence of one...
Given that the events and are such that and . Find if they are (i) mutually exclusive (ii) independent.
Solution: Given: $\mathrm{P}(\mathrm{A})=1 / 2, \mathrm{P}(\mathrm{A} \cup \mathrm{B})=1 / 5$ and let the probability of event be $\mathrm{P}(\mathrm{B})=\mathrm{p}$ (i) Mutually exclusive When A...
Let and be events with and . Are and independent?
Solution: Given: $P(E)=3 / 5, P(F)=3 / 10$ and $P(E \cap F)=1 / 5$Evaluating the value of parameter & comparing with given, $P(E) . P(F)=3 / 5 \times 3 / 10=9 / 50 \neq 1 / 5$ $\Rightarrow P(E...
Q.Without actually performing the long division, state whether the following rational numbers will have a terminating decimal expansion or a non-terminating repeating decimal expansion:
(i) ${}^{13}/{}_{3125}$ (ii) ${}^{17}/{}_{8}$ (iii) ${}^{64}/{}_{455}$ (iv) ${}^{15}/{}_{1600}$ (v) ${}^{29}/{}_{343}$ (vi)$23/{{2}^{3}}{{5}^{2}}$ (vii)...
A die marked in red and in green is tossed. Let be the event, ‘the number is even,’ and be the event, ‘the number is red’. Are A and B independent?
Solution: The dice sample space will be be $S={1,2,3,4,5,6}$ Let $A$ be the event, the number is even, sample space of the event: $\Rightarrow \mathrm{A}={2,4,6}$ $\Rightarrow P(A)=3 / 6=1 / 2$ Now,...
Discuss the trends in chemical reactivity of group 15 elements.
The general trends in chemical properties of the group – 15 are as follows:(i) Reactivity towards hydrogen:The elements present in group 15 undergo a reaction with hydrogen to form hydrides of type...
A fair coin and an unbiased die are tossed. Let A be the event ‘head appears on the coin’ and be the event on the die’. Check whether and are independent events or not.
Given: A fair coin and an unbiased die are tossed. Let A be the event head appears on the coin. So the sample space of the event will be: $\Rightarrow A={(\mathrm{H}, 1),(\mathrm{H}, 2),(\mathrm{H},...
A box of oranges is inspected by examining three randomly selected oranges drawn without replacement. If all the three oranges are good, the box is approved for sale, otherwise, it is rejected. Find the probability that a box containing 15 oranges out of which 12 are good and 3 are bad ones will be approved for sale.
Solution: Given: A box of oranges. Let A, B, and C represent the events that occur when the first, second, and third drawn oranges are all excellent. Now, $P(A)=P$ (good orange in first draw) $=12 /...
Two cards are drawn at random and without replacement from a pack of 52 playing cards. Find the probability that both the cards are black.
Given: A pack of 52 cards. As we all know, there are a total of 26 black cards. Let $A$ and $B$ represent the first and second drawn cards being black, respectively. Now if the probability of event...
If and , find if and are independent events.
Solution: Given: $P(A)=3 / 5$ and $P(B)=1 / 5$ As A and B are independent events.So we know that for independent events,$\Rightarrow P(A \cap B)=P(A) . P(B)$Substituiting the values we get, $=3 / 5...
Why is adsorption an exothermic process?
The process of adsorption is always exothermic. There are two ways to understand this which are as follows :- (I) The residual forces on the adsorbent's surface are reduced as a result of...
What is the activation of adsorbent? How is it achieved?
Activation of adsorbent is the process of increasing the adsorption power of the adsorbent. The following methods are used to activate adsorbents: (I) Increasing the adsorbent surface area. This can...
Q.Prove that the following are irrationals?
$\left( 1 \right)$ ${}^{1}/{}_{\sqrt{2}}$ $(2)7\sqrt{5}$ $(3)6+\sqrt{2}$ $\left( 1 \right)$ Let us assume, ${}^{1}/{}_{\sqrt{2}}$ is rational. Then, we can find co-prime x and y$(y\ne 0)$ such that...
Q.Prove that is irrational ?
Let us assume $3+2\sqrt{5}$ is rational. Then we can find co-prime x and y($y\ne 0$ ) such that $3+2\sqrt{5}=\frac{x}{y}$ Rearranging , we get $2\sqrt{5}=\frac{x}{y}-3$...
Q.Prove that is irrational number?
Let, $\sqrt{5}$ is rational number. Therefore ,$\sqrt{5}$ can be written as ${}^{x}/{}_{y}$ (where,x & y are coprime) $y\sqrt{5}=x$ Squaring both sides ${{(y\sqrt{5})}^{2}}={{x}^{2}}$ $$...
Why does the reactivity of nitrogen differ from phosphorus?
Nitrogen is a chemically less reactive element because of the high stability of its molecular form ${{N}_{2}}$. In nitrogen molecule, the two nitrogen atoms form a triple bond among themselves....
Distinguish between pollination and fertilization. Mention the site and product of fertilization in a flower. Draw a neat, labeled diagram of a pistil showing pollen tube growth and its entry into the ovule.
Soln: Pollination Fertilization Pollen grains are transferred from the anther to the stigma of a flower. It is the result of the union of male and female gametes. Achieved by natural forces such as...
Q.There is a circular path around a sports field. Sonia takes 18 minutes to drive one round of the field, while Ravi takes 12 minutes for the same. Suppose they both start at the same point and at the same time, and go in the same direction. After how many minutes will they meet again at the starting point?
Since, Both Sonia and Ravi move in the same direction and at the same time, The method to find the time when they will be meeting again at the starting point is LCM(Lowest Common Multiple) of 18...
Explain why and are composite numbers?
Numbers are of two types –prime numbers(two factors) & composite numbers(more then 2 factors). $(7\times 11\times 13)+13$ Taking 13 as common factor =$13[(7\times 11)+1]$ =$13(77+1)$...
Q. Check whether can end with the digit 0 for any natural number n?
If last digit of any number is 0,it should be divisible by 10. It also divisible by 2 and 5 as $10=2\times 5$ Prime factorisation of ${{6}^{n}}={{(2\times 3)}^{n}}$ By observation we can say...
Q.Given that HCF (306, 657) = 9, find LCM (306, 657)?
As we know that, HCF×LCM=Product of the two given numbers(Multiplication of two given number) Since, HCF(Highest Common Factor) is given 9 of two numbers 306 & 657 Therefore using formula...
11. Excessive exposure of humans to U V-rays results in
(i) damage to the immune system (ii) damage to lungs (iii) skin cancer (iv) peptic ulcers (a) (i) and (ii) (b) (ii) and (iv) (c) (i) and (iii) (d) (iii) and (iv) Correct option – ( c ) Explanation...
10. Flow of energy in an ecosystem is always
(a) unidirectional (b) bidirectional (c) multidirectional (d) no specific direction Correct option – ( a ) Explanation for correct option – the flow of energy in an ecosystem is always in one...
9. Organisms of a higher trophic level which feed on several types of organisms belonging to a lower trophic level constitute the
(a) food web (b) ecological pyramid (c) ecosystem (d) food chain Correct option – ( a ) Explanation for correct option – food web is composed of organisms of higher trophic level which eat several...
8. In an ecosystem, the 10% of energy available for transfer from one trophic level to the next is in the form of
(a) heat energy (b) light energy (c) chemical energy (d) mechanical energy Correct option – ( c ) Explanation for correct option – energy that is transmitted from one trophic level to another one is...
7. Organisms which synthesise carbohydrates from inorganic compounds using radiant energy are called
(a) decomposers (b) producers (c) herbivores (d) carnivores Correct option – ( b ) Explanation for correct option – producers are those which produce their own food with the help of solar energy ,...
6. Depletion of ozone is mainly due to
(a) chlorofluorocarbon compounds (b) carbon monoxide (c) methane (d) pesticides Correct option – ( a ) Explanation for correct option - in the stratosphere chlorofluorocarbon compounds are...
5. Accumulation of non-biodegradable pesticides in the food chain in increasing amount at each higher trophic level is known as
(a) eutrophication (b) pollution (c) biomagnification (d) accumulation Correct option – ( c ) Explanation for correct option – biomagnification refers to the rise in concentration of adverese...
4. In the given food chain, suppose the amount of energy at the fourth trophic level is 5 kJ, what will be the energy available at the producer level?
Grass → Grasshopper → Frog → Snake → Hawk (a) 5 k J (b) 50 k J (c) 500 k J (d) 5000 k J Correct option – ( d ) Explanation for correct option – at a particular trophic level the available energy...
3. An ecosystem includes
(a) all living organisms (b) non-living objects (c) both living organisms and non-living objects (d) sometimes living organisms and sometimes non-living objects Correct option – ( c ) Explanation...
2. In a food chain, the third trophic level is always occupied by
(a) carnivores (b) herbivores (c) decomposers (d) producers Correct option – ( a ) Explanation for correct option – carnivores are placed at the third place in the trophic level . Explanation for...
1. Which one of the following is an artificial ecosystem?
(a) Pond (b) Crop field (c) Lake (d) Forest Correct option – ( b ) Explanation for correct option – crop field is artificial ecosystem . It is an area in which plants are grown selectively ....
Q.Express each number as a product of its prime factors:
(i) 140 (ii) 156 (iii) 3825 (iv) 5005 (v) 7429 i) 140 By Taking the LCM(Lowest Common Multiple) of 140, we will get the product of its prime factor. Therefore, $140=2\times 2\times 5\times...
If and are events such that , then
A. but
B.
C.
D.
Solution:Answer: D. $P(A)=P(B)$ Explanation: Given: $\mathrm{P}(\mathrm{A} \mid \mathrm{B})=\mathrm{P}(\mathrm{B} \mid \mathrm{A})$We are aware that, according to the concept of conditional...
If , then is
A. 0
B.
C. not defined
D. 1
Answer: C. Not defined Explanation: We are aware that, according to the concept of conditional probability, $\mathrm{P}(\mathrm{A} \mid \mathrm{B})=\frac{\mathrm{P}(\mathrm{A} \cap...
Consider the experiment of throwing a die, if a multiple of 3 comes up, throw the die again and if any other number comes, toss a coin. Find the conditional probability of the event ‘the coin shows a tail’, given that ‘at least one die shows a 3 ‘.
Let $E$ be the event that 'the coin shows a tail' and $F$ be the event that 'at least one die shows a 3 '. $\Rightarrow \mathrm{E}={1 \mathrm{~T}, 2 \mathrm{~T}, 4 \mathrm{~T}, 5 \mathrm{~T}}$ and...
Consider the experiment of throwing a die, if a multiple of 3 comes up, throw the die again and if any other number comes, toss a coin. Find the conditional probability of the event ‘the coin shows a tail’, given that ‘at least one die shows a 3 ‘.
Let $E$ be the event that 'the coin shows a tail' and $F$ be the event that 'at least one die shows a 3 '. $Rightarrow mathrm{E}={1 mathrm{~T}, 2 mathrm{~T}, 4 mathrm{~T}, 5 mathrm{~T}}$ and...
Consider the experiment of throwing a die, if a multiple of 3 comes up, throw the die again and if any other number comes, toss a coin. Find the conditional probability of the event ‘the coin shows a tail’, given that ‘at least one die shows a 3 ‘.
The sample space for the experiment in question is shown in the table below. $\mathrm{S}=\left{\begin{array}{c}(3,1),(3,2),(3,3),(3,4),(3,5),(3,6), \ (6,1),(6,2),(6,3),(6,4),(6,5),(6,6) \ 1...
Given that the two numbers appearing on throwing two dice are different. Find the probability of the event ‘the sum of numbers on the dice is 4 ‘.
Solution: Let $\mathrm{E}$ be the event that 'the sum of numbers on the dice is $4^{\prime}$ and $\mathrm{F}$ be the event that 'the two numbers appearing on throwing the two dice are different. So...
An instructor has a question bank consisting of 300 easy True / False questions, 200 difficult True / False questions, 500 easy multiple choice questions and 400 difficult multiple choice questions. If a question is selected at random from the question bank, what is the probability that it will be an easy question given that it is a multiple-choice question?
Solution: There are two sorts of questions in this section: True/False and Multiple Choice Questions (T/F or MCQ), and each of these types is further subdivided into Easy and Difficult categories,...
Assume that each born child is equally likely to be a boy or a girl. If a family has two children, what is the conditional probability that both are girls given that (i) the youngest is a girl, (ii) at least one is a girl?
Solution Assume $B$ denotes boy and $G$ denote girl. Then, the sample space of the given experiment is $S={G G, G B, B G, B B}$ Let $\mathrm{E}$ be the event that 'both are girls'. $\Rightarrow...
A fair die is rolled. Consider events and . Find (i) and
(ii) and
(iii) and
Solution: The sample space for the given event is $S={1,2,3,4,5,6}$ Sample space of events,$E={1,3,5}, F={2,3}$ and $G={2,3,4,5} \ldots \ldots \ldots$ (i)The events probability of events are:...
A black and a red dice are rolled.(a) Find the conditional probability of obtaining a sum greater than 9 , given that the black die resulted in a (b) Find the conditional probability of obtaining the sum 8 , given that the red die resulted in a number less than
Solution:Assuming: B denote black coloured die and R denote red coloured die. Therefore, the sample space for the specified experiment will be as follows:...
Mother, father and son line up at random for a family picture E: son on one end, F: father in middle
Solution: We assume that $\mathrm{M}$ denote mother, $\mathrm{F}$ denote father and $\mathrm{S}$ denote son. Then, the sample space for the given experiment will be: S= { MFS, SFM, FSM, MSF, SMF,...
Mother, father and son line up at random for a family picture E: son on one end, F: father in middle
Solution: We assume that $mathrm{M}$ denote mother, $mathrm{F}$ denote father and $mathrm{S}$ denote son. Then, the sample space for the given experiment will be: S= $\{$ MFS, SFM, FSM, MSF, SMF,...
Mother, father and son line up at random for a family picture E: son on one end, F: father in middle
Solution: We assume that $\mathrm{M}$ denote mother, $\mathrm{F}$ denote father and $\mathrm{S}$ denote son. Then, the sample space for the given experiment will be: S= ${$MFS, SFM, FSM, MSF, SMF,...
A die is thrown three times, E: 4 appears on the third toss, and 5 appears respectively on first two tosses.
In the sample space, there are 216 outcomes, with each element of the sample space having three entries and taking the form $(x, y, z)$ where $1 \leq x, y, z \leq 6$. Considering the event, E: 4...
A die is thrown three times, E: 4 appears on the third toss, and 5 appears respectively on first two tosses.
Solution: In the sample space, there are 216 outcomes, with each element of the sample space having three entries and taking the form $(x, y, z)$ where $\1 leq x, y, z leq 6$. Considering the event,...
A die is thrown three times, E: 4 appears on the third toss, and 5 appears respectively on first two tosses.
Solution: In the sample space, there are 216 outcomes, with each element of the sample space having three entries and taking the form $(x, y, z)$ where $1 \leq x, y, z \leq 6$. Considering the...
Two coins are tossed once, where (i) E: tail appears on one coin, : one coin shows head
(ii) E: no tail appears, F: no head appears
Solution: Determining the sample space of the given experiment is $\mathrm{S}=\{\mathrm{HH}, \mathrm{HT}, \mathrm{TH}, \Pi\}\}$ (i) Given that, E: tail appears on one coin And F: one coin shows head...
Determine P (E|F) in: A coin is tossed three times, where (i) : head on third toss, : heads on first two tosses (ii) : at least two heads, : at most two heads (iii) : at most two tails, at least one tail
Solution: The sample space of the given experiment will be: S={HHH, HHT, HTH, THH, HTT, THT, TTH, TTT} (i) Given that, E: head-on third toss And F: heads on first two tossesSo writing the sample...
If and , find
(i)
(ii)
(iii)
Solution: Given: $\mathrm{P}(\mathrm{A})=\frac{6}{11}, \mathrm{P}(\mathrm{B})=\frac{5}{11}, \mathrm{P}(\mathrm{A} \cup \mathrm{B})=\frac{7}{11}$ (i) We know that $\mathrm{P}\left(\mathrm{A}^{*}...
Evaluate , if and .
Solution: i) Given relation $2 \mathrm{P}(\mathrm{A})=\mathrm{P}(\mathrm{B})=\frac{5}{13}$ and $\mathrm{P}(\mathrm{A} \mid \mathrm{B})=\frac{2}{5}$ $\Rightarrow \mathrm{P}(\mathrm{B})=\frac{5}{13},...
If and , find
(i)
(ii)
(iii) P (A U B)
Solution:Given $\mathrm{P}(\mathrm{A})=0.8, \mathrm{P}(\mathrm{B})=0.5$ and $\mathrm{P}(\mathrm{B} \mid \mathrm{A})=0.4$ (i) By definition of conditional probability, we know that,...
Compute , if and
Solution: Given: $P(B)=0.5$ and $P(A \cap B)=0.32$ We know this because conditional probability is defined as follows: $\mathrm{P}(\mathrm{A} \mid \mathrm{B})=\frac{\mathrm{P}(\mathrm{A} \cap...
Given that and are events such that and , find and
Solution: Given: $P(E)=0.6, P(F)=0.3$ and $P(E \cap F)=0.2$ We know this because conditional probability is defined as follows: $P(A \mid B)=\frac{P(A \cap B)}{P(B)}$ By substituting the values we...
An army contingent of 616 members is to march behind an army band of 32 members in a parade. The two groups are to march in the same number of columns. What is the maximum number of columns in which they can march?
Given, Number of army contingent members=616 Number of army band members = 32 When we find the HCF(616,32) then we get maximum number of columns in which they can march. We use Euclid’s...
Check whether (5, – 2), (6, 4) and (7, – 2) are the vertices of an isosceles triangle.
We know that in an isosceles triangle, length of two sides is equal. We know that formula to find the distance (d) between two points $\left( {{x}_{1}},{{y}_{1}} \right)$and $\left(...
Determine if the points (1, 5), (2, 3) and (-2, -11) are collinear.
All three points are collinear if the total of the lengths of any two line segments equals the length of the third line segment. Consider the following values, A = (1, 5) B = (2, 3) and C = (-2,...
Show that any positive odd integer is of the form 6q + 1, or 6q + 3, or 6q + 5, where q is some integer.
Let a be any positive integer and b=6.Then,by Euclid’s algorithm, $a=6q+r$ for some integer $q\ge 0$ and r=0,1,2,3,4,5 because $0\le r<6$ . Therefore, $a=6q$ or $6q+1$ or $6q+2$ or $6q+3$...
Find the distance between the following pairs of points:
(i) (2, 3), (4, 1) (ii) (-5, 7), (-1, 3)(iii) (a, b), (- a, – b) We know that formula to find the distance (d) between two points $\left( {{x}_{1}},{{y}_{1}} \right)$and $\left( {{x}_{2}},{{y}_{2}}...
Use Euclid’s division algorithm to find the HCF of:
(1)We have 225>135 So, we apply the division lemma to 225 & 135 to obtain 225=135×1+90 Here remainder 90≠0, we apply the division lemma again to 135 and 90 to obtain 135=90×1+45 We consider...
53. Why is the flow of signals in a synapse from axonal end of one neuron to dendritic end of another neuron but not the reverse?
Solution - travelling of the electrical impulses takes place in the neurons . When it is transmitted to another neuron it takes the form of the neurotransmitter . Neurotransmitter are...
51. “Nervous and hormonal systems together perform the function of control and coordination in human beings.” Justify the statement.
Solution : the function of control and coordination is regulated by the hormonal and nervous system . All the organs and organ system in the body are under the control of the brain . Brain controls...
50. What are reflex actions? Give two examples. Explain a reflex arc .
Solution – reflex action is a rapid and involuntary response to a stimulus . Examples of reflex action are – in bright light the pupil of the changes in size . ...
49. Name various plant hormones. Also give their physiological effects on plant growth and development.
Solution – some of the plant hormones are gibberellin – it is responsible for the growth of the stemauxin – it causes the cell to elongateabscisic acid – the growth of the plant is halted and...
48. Mention one function for each of these hormones :
(a) Thyroxin (b) Insulin (c) Adrenaline (d) Growth hormone (e) Testosterone. Solution – (a) Thyroxin : it is important in the role of digestion , heart and muscle function , development of brain and...
47. What constitutes the central and peripheral nervous systems? How are the components of the central nervous system protected?
Solution – Brain and spinal cord makes up the central nervous system . peripheral nervous system comprises of nerves which are present outside the spinal cord . Central nervous system is very well...
46. What are the major parts of the brain? Mention the functions of different parts.
Solution – major parts of the brain along with their functions are – forebrain - it has an important role in information processing , sensory and associative functions and voluntary motor...
45. Draw the structure of a neuron and explain its function.
Solution - neurons transmit information among the different areas of the brain and rest of the nervous system . Structure of the neuron – Cell body have dendrites which are responsible to receives...
43. Answer the following :
(b) Dwarfism results due to deficiency of which hormone? (a) Which hormone is responsible for the changes noticed in females at puberty? (c) Blood sugar level rises due to deficiency of which...
42. What happens at the synapse between two neurons?
Solution – electrical impulse releases chemicals at the end of the axon . These chemicals cross the synapse and in the dendrite similar electrical impulses are created .
41. What will happen if the intake of iodine in our diet is low ?
Solution – our metabolism is controlled by thyroid hormone . Low levels of iodine results in low thyroid function and also causes abnormal enlargement of the thyroid gland ( hypothyroidism ) known...
40. What is a tropic movement? Explain with an example .
Solution – when a plant shows some growth movement in response to a stimulus then it is known at tropic movement . Movement can be either direction that is it can be towards the stimulus or away...
39. Match the terms of Column (A) with those of Column (B)
Column AColumn B(a) Olfactory receptors(i) Tongue(b) Thermo receptors (temperature receptors)(ii) Eye(c) Gustatoreceptors(iii) Nose(d) Photoreceptors(iv) Skin solution Column AColumn B(a) Olfactory...
38. Label the parts of a neuron in Figure 7.5.
Figure Solution – DendriteCell bodyAxonAxon terminal
37. In Figure 7.4 (a), (b) and (c), which appears more accurate and why?
Figure Solution – figure ( a ) is more accurate . It is so because the plant is showing the ideal condition that is the roots are showing positive geotrophism and the shoot system is showing...
36. Label the endocrine glands in Figure 7.3.
figure Solution – Pineal glandPituitary glandThyroid glandThymus
35. Name the plant hormones responsible for the following
(a) elongation of cells (b) growth of stem (c) promotion of cell division (d) falling of senescent leaves. Solution – (a) elongation of cells – Auxin (b) growth of stem – gibberellin (c) promotion...
34. Label the parts (a), (b), (c) and (d) and show the direction of flow of electrical signals in Figure 7.2.
Solution – Sensory neuron Spinal cord Motor neuron Muscle Flow of electrical signals: Receptors in hand ==> Sensory neurons ==. Spinal cord (CNS) ==>Motor neurons ==> Effector - muscles in...
33. In humans, the life processes are controlled and regulated by
(a) reproductive and endocrine systems (b) respiratory and nervous systems (c) endocrine and digestive systems (d) nervous and endocrine systems Correct option – ( d ) Explanation for correct option...
30. The hormone which increases the fertility in males is called
(a) oestrogen (b) testosterone (c) insulin (d) growth hormone Correct option – ( b ) Explanation for correct option – Testosterone is the male sex hormone produces in testes of males which promotes...
29. A doctor advised a person to take an injection of insulin because
(a) his blood pressure was low (b) his heart was beating slowly (c) he was suffering from goitre (d) his sugar level in blood was high Correct option – ( d ) Explanation for correct option –...
Shown Below are some of the cell organelles.
Can you identify these? The given cells are, 1.Mitochondria which is the power house of the cell. 2.Centrosome which is present in the animal cell alone and contains one or two centrioles. 3.Golgi...