1

A man standing on a lift that is descending does not feel any weight because

A

the inside of the lift is air tight

B

the lift is in vacuum

C

there is no reaction from the floor of the lift

D

there is no gravitational pull on the man in the lift

CORRECT OPTION:
c

The resultant force acting on the man is given by w = mg - R

Mg - mg = 0

The man feels weightless because the reaction, R is equal to the weight mg

Mg - mg = 0

The man feels weightless because the reaction, R is equal to the weight mg

2

Two balls X and Y weighing 5 g and 50 kg respectively were throne up vertically at the same time with a velocity of 100 ms^{1} .How will their positions be one second later?

A

X and Y will be 500 m from each other

B

Y will be 500 m ahead of X

C

X will be 500 m ahead of Y

D

X and Y both be 500 m from the poin of throw

CORRECT OPTION:
d

v^{2} = U^{2} - 2G s

0 = 100^{2} - 2 x 10 x s = 10000 - 20s

s = (10000)/20 = 500m

Which is independent of mass.the two bodies where acted upon by the same retarding force of gravity which is independent of mass of the body; therefore both will be 500 m from the point of throw.

0 = 100

s = (10000)/20 = 500m

Which is independent of mass.the two bodies where acted upon by the same retarding force of gravity which is independent of mass of the body; therefore both will be 500 m from the point of throw.

3

If it takes an object 3s to fall freely to the ground from a certain height, what is the distance covered by the object?

A

90 m

B

30 m

C

45 m

D

60 m

CORRECT OPTION:
c

S = (1)/2gt^{2}

S = (1)/2 x (10)/1 x 3^{2} =5 x 9 = 45 m

S = (1)/2 x (10)/1 x 3

4

An object of mass 2 kg moves with a velocity of 10 ms^{1} round at circle of radius 4 m. Calculate the centripetal force on the object

A

25 N

B

100 N

C

50 N

D

40 N

CORRECT OPTION:
c

Centripetal force,

F = \( \frac{mv^2}{r} \)

= \( \frac{2 \times 10^2}{4} \)

= \( \frac{200}{4} \)= 50N

F = \( \frac{mv^2}{r} \)

= \( \frac{2 \times 10^2}{4} \)

= \( \frac{200}{4} \)= 50N

5

A carpenter on top of a roof of 20.0m high dropped a hammer of mass 1.5 kg and it fell directly to the ground. the kinetic energy of the hammer just before hitting the ground is?

[g = 10 ms^{-2}]

[g = 10 ms

A

600 J

B

150J

C

300 J

D

450 J

CORRECT OPTION:
c

K e just before hitting the gound

= P e at the maximum height (conservation of mechanical energy)

K e = P e = mgh = 1.5 x 10 x 20

= 300 J

= P e at the maximum height (conservation of mechanical energy)

K e = P e = mgh = 1.5 x 10 x 20

= 300 J

6

If a tube of small radius opened at both ends is placed in a liquid, the liquid will

A

remain at the same level irrespective of whether the liquid wet the glass or not

B

fall below the liquid level if the liquid wets the glass

C

falls below the liquid level if the liquid does not wet the glass

D

rise above the liquid level if the liquid does not wet the glass

CORRECT OPTION:
c

The liquid will rise up the capillary if it wets glass and falls below its wets glass and falls below its initial level if it does not wet glass

7

An object weighs 22 kg in water and 30kg in air. what is the upthrust exerted by the liquid on the object.

[g = 10 ms^{2}]

[g = 10 ms

A

50 N

B

520 N

C

220 N

D

80 N

CORRECT OPTION:
d

upthrust = weight in air - weight in liquid = 30 x 10 - 22 x 10 = 300 - 220 = 80 N

8

A metal of volume 40 cm^{3} is heated from 30 °c to 90 °c, the increase in volume is

A

0.12 cm^{3}

B

4.00 cm^{3}

C

1.20 cm^{3}

D

0.40 cm^{3}

CORRECT OPTION:
e

Correct Answer: Option E
increase in volume, DV = RV_{1} ∆ θ = 3α Vsub>1

9

A copper wire was subjected to a tensile stress of 7.7 x 10^{7} x 10 Nm^{-2}. calculate strain of the wire.

[young modules = 1.1 x 10^{11} Nm^{-2}]

[young modules = 1.1 x 10

A

2. 0 x 10^{-5}

B

7.0 x 10^{-3}

C

7.0 x 10^{-4}

D

2.2 x 10^{-4}

CORRECT OPTION:
c

Young modules = \( \frac{\text{Tensile stress}}{\text{Tensile strain}}\)

= \( 1.1 \times 10^11 = \frac{7.7 \times 10^7}{\text{Tensile Strain}} \)

∴ Tensile strain = \( \frac{7.7 \times 10^7}{1.1 \times 10^11} \)

= \( 7.0 \times 10^{7-11}

= 7.0 \times 10^{-4} \)

= \( 1.1 \times 10^11 = \frac{7.7 \times 10^7}{\text{Tensile Strain}} \)

∴ Tensile strain = \( \frac{7.7 \times 10^7}{1.1 \times 10^11} \)

= \( 7.0 \times 10^{7-11}

= 7.0 \times 10^{-4} \)

10

I. High thermal capacity.

II. High sensitivity.

III.Easy readability.

IV. Accuracy over a wide range of temperature

From the statement above, the qualities of a good thermometer are

II. High sensitivity.

III.Easy readability.

IV. Accuracy over a wide range of temperature

From the statement above, the qualities of a good thermometer are

A

I and II

B

I, II,III and IV

C

I, III and IV

D

II, III and IV

CORRECT OPTION:
d

A good thermometric liquid should not have a high thermal capacity so that the themperetue of the body being measured will not be affected

∴ II, III and IV are qualities of a good thermometer

∴ II, III and IV are qualities of a good thermometer

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