# Work, Energy and Power (KVPY (Kishore Vaigyanik Protsahan Yojana) Stream SB-SX (Class 12 & 1st Year B.Sc.) Physics): Questions 14 - 18 of 21

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## Question number: 14

» Work, Energy and Power » Work Done

MCQ▾

### Question

A particle of mass 1 kg has potential energy, . At, the particle is at rest (5,3). Work done by external force to displace the particle from rest to the point of crossing the x axis is –

### Choices

Choice (4) Response

a.

13 J

b.

c.

d.

169 J

## Question number: 15

» Work, Energy and Power » Conservative and Non-Conservative Forces

Appeared in Year: 2014

MCQ▾

### Question

A 1.5 kW (kilo-watt) laser beam of wavelength 6400 Å is used to levitate a thin aluminum disc of same area as the cross-section of the beam. The laser light is reflected by the aluminum disc without any absorption. The mass of the foil is close to

### Choices

Choice (4) Response

a.

b.

c.

d.

## Question number: 16

» Work, Energy and Power » Work-Energy Theorem

MCQ▾

### Question

A moving particle of mass m makes a head – on – collision with a particle of mass 3 m initially at rest. If the collision is perfectly elastic, the percentage loss of energy of the colliding particle is –

### Choices

Choice (4) Response

a.

50 %

b.

60 %

c.

75 %

d.

100 %

## Question number: 17

» Work, Energy and Power » Work Done

MCQ▾

### Question

A block of mass 25 kg slides down a rough slope which is inclined at 450 to the horizontal. The coefficient of sliding friction is 0.30. When the block has slid 15 m, the work done on the block by the force of friction is nearly,

### Choices

Choice (4) Response

a.

b.

c.

795.45 J

d.

## Question number: 18

» Work, Energy and Power » Conservative and Non-Conservative Forces

Appeared in Year: 2015

MCQ▾

### Question

Two small metal balls of different mass m1 and m2 are connected by strings of equal length to fixed point. When the balls are given charges, the angles that the two strings make with the vertical are 300 and 600, respectively. The ratio is close to –

### Choices

Choice (4) Response

a.

3.0

b.

1.7

c.

0.58

d.

2.0

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