M.C.Q. [1 M]

MCQ 11 Mark

The enrichment of water bodies with nutrients leading to excessive growth of phytoplankton is known as:-

A
Ammonification
B
Nitrification
✓
Eutrophication
D
Phyto-enrichment

Answer

Correct option: C.

Eutrophication

(c) Eutrophication
Explanation: The enrichment of water bodies with nutrients leading to excessive growth of phytoplankton is called

Eutrophication. Eutrophication or more precisely hypertrophication, is the enrichment of a water body with nutrients,

usually with an excess amount of nutrients. This process induces the growth of plants and algae and due to the biomass load,

may result in oxygen depletion of the water body.

Eutrophication is an enrichment of water by nutrient salts that causes structural changes to the ecosystem such as increased

production of algae and aquatic plants, depletion of fish species, general deterioration of water quality, and other effects that

reduce and preclude use. Eutrophication is almost always induced by the discharge of phosphate-containing detergents,

fertilizers, or sewage into an aquatic system.

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MCQ 21 Mark

Select the correct statement(s).
i.A solution in which size of the solute particles is about 10-10 m, is called true solution.
ii.A solution which contains maximum possible amount of solute at any given temperature is called a saturated solution.
iii.In suspension, the size of particles is of the order of 107 m or larger
iv. A colloid is a heterogeneous system

✓
I, II, III and IV
B
I and II only
C
III and IV only
D
I, III and IV only

Answer

Correct option: A.

I, II, III and IV

(a) I, II, III and IV
Explanation: I, II, III and IV

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MCQ 31 Mark

A change is said to be a physical change when

A
No energy change occurs
✓
All statements are correct
C
The change can be easily reversed
D
No new substances are formed

Answer

Correct option: B.

All statements are correct

(b) All statements are correct
Explanation: Some of the characteristics of a physical change are:

i. Temporary in nature.

ii. No energy change occur.

iii. Does not affect the internal structure of a substance, only the molecules are rearranged.

iv. No new substance is formed.

So all statements are correct.

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MCQ 41 Mark

Plasmolysis in a plant cell is defined as

A
shrinkage of nucleoplasm
✓
shrinkage of cytoplasm in hypertonic medium
C
break down (lysis) of plasma membrane in hypotonic medium
D
shrinkage of nucleolus

Answer

Correct option: B.

shrinkage of cytoplasm in hypertonic medium

(b) shrinkage of cytoplasm in hypertonic medium
Explanation: Plasmolysis is mainly known as shrinking of cell membrane in hypertonic solution and great pressure.

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MCQ 51 Mark

To prepare a mount of human cheek cell, the sample is collected from:

A
outer side of cheek with a blade
✓
inner side of cheek with a toothpick
C
inner side of cheek with a blade
D
outer side of cheek with a toothpick

Answer

Correct option: B.

inner side of cheek with a toothpick

(b) inner side of cheek with a toothpick
Explanation: While preparing a mount of human cheek cell, the sample is collected from the inner side of the cheek using a

toothpick, which will collect some cheek cells.

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MCQ 61 Mark

If K, L, M, N, shells of an atom are full. The total number of electrons in that atom are:

A
26
B
36
✓
60
D
42

Answer

Correct option: C.

Maximum number of electrons in L-shell = 8

Maximum number of electrons in M-shell = 18

Maximum number of electrons in N-shell = 32

2 + 8 + 18 + 32 = 60

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MCQ 71 Mark

The speed of a train increases at a constant rate a from zero to $v,$ and then remains constant for an interval, and finally decreases to zero at a constant rate $p.$ If $L$ be the total distance travelled, then the total time taken is

A
$\frac{t}{2}+\frac{1}{v}\left(\frac{1}{a}+\frac{1}{b}\right)$
✓
$\frac{L}{v}+\frac{v}{3}\left(\frac{1}{0}+\frac{1}{8}\right)$
C
$\frac{2}{v}+\frac{2}{y}\left(\frac{1}{a}+\frac{1}{a}\right)$
D
$\frac{t}{v}+2 v\left(\frac{1}{a}+\frac{1}{8}\right)$

Answer

Correct option: B.

$\frac{L}{v}+\frac{v}{3}\left(\frac{1}{0}+\frac{1}{8}\right)$

Velocity increases from $0$ to $v :$
We know that $v = u + at$
Here, $u =0, v = v , a =\alpha$
$\therefore t =\frac{v}{\alpha}$
and $s = ut +\frac{1}{2} at ^2 ;$
$s _1=\frac{v^2}{2 \alpha}$
Velocity decreases from $v$ to $0 :$
Here, $u = v , v =0, a =-\beta$
Using $v = u + at$
$\Rightarrow t=\frac{v}{\beta}$
and $s = ut +\frac{1}{2} at ^2 ;$
$s _2=\frac{v^2}{2 \beta}$
So, distance travelled during acceleration and retardation,$d=s_1+s_2=\frac{y^2}{2}\left(\frac{1}{\alpha}+\frac{1}{\beta}\right)$
Thus, distance travelled during constant velocity $S_3=L-\frac{v^2}{2}\left(\frac{1}{\alpha}+\frac{1}{\beta}\right)$

So, time taken to travel this distance

$t=\frac{L-\frac{v^2}{2}\left(\frac{1}{\alpha}+\frac{1}{\beta}\right)}{v}=\frac{L}{v}=\frac{v}{2}\left(\frac{1}{\alpha}+\frac{1}{\beta}\right)$

Hence, total time taken to cover distance $L=\left(\frac{v}{\alpha}\right)+\left[\frac{L}{v}-\frac{v}{2}\left(\frac{1}{\alpha}+\frac{1}{\beta}\right)\right]+\left(\frac{v}{\beta}\right)$
$=\frac{L}{v}+\frac{2}{v}\left(\frac{1}{\alpha}+\frac{1}{\beta}\right)$

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MCQ 81 Mark

The position of the water level, in a measuring cylinder, before and after immersing a solid in it, are as shown in the figure given below. The volume of the given solid $($in $cm^{3})$

A
$2.2$
✓
$1.8$
C
$4.2$
D
$6.6$

Answer

Correct option: B.

$1.8$

Volume of block $=$ change in level by volume $= (4.2 – 2.4) = 1.8 \ cm^3$

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MCQ 91 Mark

Smooth muscle consists of ____________ filaments that are not arranged into sarcomeres giving it a non-striated pattern.

A
plain and large
B
curved and large
✓
thick and thin
D
long and straight

Answer

Correct option: C.

thick and thin

(c) thick and thin
Explanation: Smooth muscle consists of thick and thin filaments that are not arranged into sarcomeres giving it a non-striated

pattern.

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MCQ 101 Mark

What are a and b?

A
a = divide by 22.4 L, b -multiply by 22.4 L
B
a = divide by 22.4 L, b = divide by 22.4 L
C
a = multiply by 22.4 L, b multiply by 22.4 L
✓
a = multiply by 22.4 L, b = divide by 22.4 L

Answer

Correct option: D.

a = multiply by 22.4 L, b = divide by 22.4 L

(d) a multiply by 22.4 L, b divide by 22.4 L
Explanation: Volume of gas at STP $=$ No. of moles $\underbrace{\times 22.4 L}_a$
No. of moles $=$ Volume of gas at STP $\underbrace{\div 22.4 L}_b$

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MCQ 111 Mark

Which of the following is correct for the given figure?

A
The parts labelled 'a', 'b' and 'c', all possess photosynthetic pigments such as chlorophyll.
✓
The part labelled 'a' is the site of dark reaction.
C
The part labelled 'c' is called granum
D
The part labelled 'b' is called intergranal thylakoid

Answer

Correct option: B.

The part labelled 'a' is the site of dark reaction.

(b) The part labelled 'a' is the site of dark reaction.
Explanation: The given figure is of chloroplast. The part labelled ‘a’ is stroma. The part labelled ‘b’ is called grana where

light reaction of photosynthesis takes place. The part labelled ‘c’ is intergranal thylakoid. Photosynthetic pigments such as

chlorophyll are present only in thylakoid membranes (grana + intergranal thylakoids) and not in stroma or nongranal

thylakoids.

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MCQ 121 Mark

Nerve cell does not contain

A
axon
B
nerve endings
C
dendrites
✓
tendons

Answer

Correct option: D.

tendons

(d) tendons
Explanation: Each nerve cell or neuron Is composed of three parts
i. Cyton or cell body It contains central nucleus and cytoplasm with characteristic deeply stained particles called Nissl’s granules (i.e., clumps of ribosome).
ii. Dendron These are short processes arising from cyton and further branching into dendrites.
iii. Axon It is a single long cylindrical process of uniform diameter which forms fine branches terminally. The dendrites receives impulses and the axon takes impulses away from the cell body.

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MCQ 131 Mark

Which of the following is the fastest growing carp?

A
Singhara
B
Rohu
C
Mrigal
✓
Catla

Answer

Correct option: D.

Catla

(d) Catla
Explanation: Catla is the fastest growing Indian major carp species and widely distributed throughout India, Nepal, Pakistan, Burma, and Bangladesh.

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MCQ 141 Mark

Which of the following gives both direction and magnitude?

A
Unit Scalar
B
Scalar
C
Unit Vector
✓
Vector

Answer

Correct option: D.

Vector

(d) Vector
Explanation: Any quantity that needs to be fully described by identifying its magnitude and direction is referred to as a vector quantity. By magnitude, we mean the size of the quantity, such as length or strength. By direction, we mean where the vector is pointing or where it is being directed, such as left or right, north, south, east, or west, or even up or down.

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MCQ 151 Mark

Engulfing of food materials or foreign bodies by cells like Amoeba is called:

A
plasmolysis
B
diffusion
C
osmosis
✓
endocytosis

Answer

Correct option: D.

endocytosis

(d) endocytosis
Explanation: The cell membranes flexibility allows the cell engulf in food and other material from its external environment. This process is known as endocytosis.

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MCQ 161 Mark

Which one of the following is the correct set up to determine the melting point of ice?

A
I
✓
III
C
IV
D
II

Answer

Correct option: B.

III

(b) III
Explanation: The bulb of the thermometer should be dipped in crushed ice to determine the melting point of ice.

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