# KVPY (Kishore Vaigyanik Protsahan Yojana) Stream-SA (Class 11) Physics: Questions 102 - 104 of 253

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## Question number: 102

Appeared in Year: 2014

MCQ▾

### Question

A machine is blowing spherical soap bubbles of different radii filled with helium gas. It is found that if the bubbles have a radius smaller than 1 cm, then they sink to the floor in still air. Larger bubbles float in the air. Assume that the thickness of the soap film in all bubbles is uniform and equal. Assume that the density of soap solution is same as that of water (= 1000 kg m–3). The density of helium inside the bubbles and air are 0.18 kg m–3 and 1.23 kg m–3, respectively. Then the thickness of the soap film of the bubbles is (note 1 μm = 10–6 m)

### Choices

Choice (4) Response

a.

7.00 μm

b.

0.50 μm

c.

1.50 μm

d.

3.60 μm

## Question number: 103

MCQ▾

### Question

Consider the following statements. The correct statement regarding an isobar is,

(i) Isobars are chemically different but physically same.

(ii) Isobars are atoms of different elements.

(iii) Numbers of electrons in isobars are different

(iv) The atomic numbers are same in isobars.

Select any one of following,

### Choices

Choice (4) Response

a.

(ii) and (iv) are correct

b.

(i), (ii) and (iii) are correct

c.

(iii) and (iv) are correct

d.

(i) and (iii) are correct

## Question number: 104

MCQ▾

### Question

A box when dropped from a certain height reaches the ground with a speed V. When it slides from rest from the same height down a rough inclined plane inclined at an angle 60° to the horizontal, it reaches the ground with a speed. The coefficient of sliding friction between the box and the plane is (acceleration due to gravity is 10 ms-2)

### Choices

Choice (4) Response

a.

b.

c.

d.

f Page