modern and space physics, sources of energy - Category wise Question and Answer Practice Test with Solutions

Question : 11

Select the correct statement(s) from the following.

1. In conductors, the valence and conduction bands may overlap.
2. Substances with energy gap of the order of 10 eV are insulators.
3. The resistivity of a semiconductor increases with increase in temperature.
4. The conductivity of a semiconductor increases with increase in temperature.

a) I and III only

b) I, II and IV

c) I and II only

d) I, II, III and IV

Question : 12

Match the Column I and Column II.

a) (A) → (2); (B) → (1); (C) → (4); (D) → (3)

b) (A) → (1); (B) → (2); (C) → (3); (D) → (4)

c) (A) → (3); (B) → (1); (C) → (2); (D) → (4)

d) (A) → (1); (B) → (3); (C) → (2); (D) → (4)

Question : 13 [NDA]

Which one of the following is the correct sequence of the wavelengths of radiations ?

a) IR > Green > UV > Hard X-rays

b) UV > Hard X-rays > IR > Green

c) UV > Green > IR > Hard X-rays

d) IR > Hard X-rays > Green> UV

Question : 14

Consider the following statements: A person in a spaceship located half way between the earth and the sun will notice that the :

1. sky is jet black.
2. stars do not twinkle.
3. temperature outside the spaceship is much higher than that on the surface of the earth.

a) 1 and 2

b) 1 and 3

c) 3 only

d) 1, 2 and 3

Question : 15 [CDS]

Television signal cannot be received generally beyond a particular distance due to

a) weakness of antenna

b) weakness of signal

c) curvature of the Earth

d) absorption of signal in air