KVPY Stream-SA (Class 11) Physics: Questions 100 - 102 of 252

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Question number: 100

» Ray Optics » Resolving Power of Microscopes and Astronomical Telescopes

MCQ▾

Question

The eye is natural optical instrument. Because,

(1) It can adjust aperture

(2) It can focusing according to distance by changing focal length of lens

(3) It can adjust intensity of light

(4) Focal length remains fix

Select the correct option,

Choices

Choice (4) Response

a.

(1) and (2) correct

b.

(2) and (3) correct

c.

(1) and (4) correct

d.

(1), (2) & (3) are correct

Question number: 101

» Thermodynamics » Thermal Equilibrium

Appeared in Year: 2014

MCQ▾

Question

An aluminum piece of mass 50 g initially at 300 °C is dipped quickly and taken out of 1 kg of water, initially at 30° C. if the temperature of the aluminum piece immediately after being taken out of the water is found to be 160°C, what is the temperature of the water then? (Specific heat capacities of aluminum and water are 900 J kg–1 K–1 and 4200 J kg–1, respectively. )

Choices

Choice (4) Response

a.

31.5°C

b.

45°C

c.

28.5°C

d.

165°C

Question number: 102

» Properties of Solids & Liquids » Application of Surface Tension

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

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