# KVPY (Kishore Vaigyanik Protsahan Yojana) Stream-SA (Class 11) Physics: Questions 199 - 203 of 253

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## Question number: 199

MCQ▾

### Question

The activity of a radioactive sample reduces to of its original value in 2 hours. What will be its activity in 6 hours?

### Choices

Choice (4) Response

a.

b.

c.

d.

## Question number: 200

MCQ▾

### Question

The energy required to accelerate a car from rest to 12 ms-1 is E. What energy will be required to accelerate the car from 12 ms-1 to 24 ms-1?

### Choices

Choice (4) Response

a.

E

b.

7E

c.

5E

d.

3E

## Question number: 201

MCQ▾

### Question

A train of length l (180 m) is going towards north directional constant speed v1=16 m/s. A parrot flies at a constant speed of v2 = 4 m/s towards south parallel to be railway track. The time taken by the parrot to cross the train is –

### Choices

Choice (4) Response

a.

7 s

b.

3 s

c.

9 s

d.

5 s

## Question number: 202

MCQ▾

### Question

The isotopes 238U and 235U occur in nature in the ratio 150: 1. Assuming that at the time of earth formation they were present in equal amount; make an estimation of the age of the earth. The half-lives of 238U and 235U are and respectively.

### Choices

Choice (4) Response

a.

b.

c.

d.

## Question number: 203

MCQ▾

### Question

The height of a waterfall is 75 m, If the water at the bottom of the fall is at rest. Calculate the difference between temperature of water at the top and bottom of the fall (specific heat of water and ).

### Choices

Choice (4) Response

a.

0.175 0C

b.

0.97 0C

c.

0.126 0C

d.

0.117 0C

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