Light, Heat, Thermodynamics, Wave Motion, Sound, Optics & Oscillations - Category Wise Question And Answer Practice Test With Solutions

Question : 21

Thermal conductivity of aluminium, copper and stainless steel increases in the order

a) Stainless Steel < Aluminium < Copper

b) Copper < Aluminium < Stainless Steel

c) Aluyminium < Copper < Stainless Steel

d) Copper < Stainless Steel < Aluminium

Question : 22

According to the kinetic theory of gases

a) at any instant one-third of the total atoms are moving along x-axis

b) all the atoms move horizontally with equal speeds

c) an atom moves faster during its downward motion than its upward motion

d) None of these

Question : 23 [IAS (Pre) 1993]

When there is depletion of ozone in the stratosphere, the wavelength of radiation striking the Earth’s surface will be

a) $10^{-2}$ m

b) 10^–7 m

c) 10^–10 m

d) 100 m

Question : 24

Consider the following statements:

1. Loudness or softness of a sound is determined by its amplitude.
2. Two sounds of same loudness and pitch can be distinguished by quality.
3. The speed of sound decreases on increasing the temperature.

a) 2 and 3

b) 1 and 2

c) 1 and 3

d) 1, 2 and 3

Question : 25 [IAS (Pre) 2003]

Diffusion of light in the atmosphere takes place due to

a) Helium

b) Dust particles

c) Carbon dioxide

d) Water vapours