KVPY Stream-SA (Class 11) Physics: Questions 35 - 38 of 242

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Question number: 35

» Work, Energy and Power » Power

Appeared in Year: 2011

MCQ▾

Question

A 750 W motor drivers a pump which lifts 300 liters of water per minute to a height of 6 meters. The efficiency of the motor is nearly (take acceleration due to gravity to be 10 m/s 2)

Choices

Choice (4) Response
a.

30%

b.

20%

c.

50%

d.

40%

Question number: 36

» Laws of Motion » Equilibrium of Concurrent Forces

Appeared in Year: 2012

MCQ▾

Question

A ball falls vertically downward and bounces off a horizontal floor. The speed of the ball just before reaching the floor (u1) is equal to the speed just after leaving contact with the floor (u2); u1 = u2. The corresponding magnitudes of accelerations are denoted respectively by a1 and a2. The air resistance during motion is proportional to speed and is not negligible. If g is acceleration due to gravity, then:

Choices

Choice (4) Response
a.

a1 = a2 ≠ g

b.

a1 > a2

c.

a1 = a2 = g

d.

a1 < a2

Question number: 37

» Properties of Solids & Liquids » Heat Transfer » Conduction

Appeared in Year: 2012

MCQ▾

Question

In the Arctic region hemispherical houses called Igloos are made of ice. It is possible to maintain inside an Igloo as high as 200 C because:

Choices

Choice (4) Response
a.

ice has higher density than water

b.

ice has high thermal conductivity

c.

ice has high specific heat

d.

ice has low thermal conductivity

Question number: 38

» Current Electricity » Electric Current

Appeared in Year: 2012

MCQ▾

Question

Which of the following statements is true about the flow of electrons in an electric circuit?

Choices

Choice (4) Response
a.

Electrons always flow from higher to lower potential

b.

Electrons always flow from lower to higher potential

c.

Electrons flow from higher to lower potential, except through power sources

d.

Electrons flow from lower to higher potential except through power sources

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