Questions and answers for exam Preparation

MCQs

Total Questions : 150 | Page 7 of 15 pages

Question 61. Indiscriminate disposal of used fluorescent electric lamps causes mercury pollution in the environment. Why is mercury uses in the manufacture of these lamps?

A mercury coating on the inside of the lamp makes the light bright white
When the lamp is switched on, the mercury in the lamp causes the emission of ultra-violet radiations
When the lamp is switched on, it is the mercury which converts the ultra-violet energy into visible light
None of the statements given above is correct about the use of mercury in the manufacture of fluorescent lamps

Discuss Question

Answer: Option B. -> When the lamp is switched on, the mercury in the lamp causes the emission of ultra-violet radiations
:
B
Option:(b)

Question 62. When the same note is played on a sitar and a flute, the sound produced can be distinguished from each other because of the difference in

pitch, loudness and quality
pitch and loudness
quality only
loudness only

Discuss Question

Answer: Option C. -> quality only
:
C
Option: (c)

Question 63. The technique used to transmit audio signals in television broadcasts is

Amplitude Modulation
Frequency Modulation
Pulse Code Modulation
Time Division Multiplexing

Discuss Question

Answer: Option B. -> Frequency Modulation
:
B
Option:(b)

Question 64. When a mirror is rotated by an angle θ, the reflected ray will rotate by

0o
θ/2
θ
2θ

Discuss Question

Answer: Option D. -> 2θ
:
D
Option:(d)

Question 65. An air bubble in water will act like a

convex mirror
convex lens
concave mirror
concave lens

Discuss Question

Answer: Option D. -> concave lens
:
D
Option:(d)

Question 66. A parachutist jumps from a height of 5000 m. The relationship between his falling speed, v and the distance fallen through, d is best represented as

Discuss Question

Answer: Option D. -> concave lens
:
D
Option:(d)

Question 67. Match List I (Quantity) with List II (Units) and select the correct answer using the codes given below the lists

A -2 B-1 C -3 D -4
A -1 B-2 C -4 D -3
A -1 B-2 C -3 D -4
A -2 B-1 C -4 D -3

Discuss Question

Answer: Option C. -> A -1 B-2 C -3 D -4
:
C
Option:(c)

Question 68. Cryogenic engines find applications in

sub-marine propulsion
frost-free refrigerators
rocket technology
researcher in superconductivity

Discuss Question

Answer: Option C. -> rocket technology
:
C
Option:(c)

Question 69. Assertion (A): Radio waves bend in a magnetic field.
Reason (R): Radio waves are electromagnetic in nature.
Codes

Both A and R are true and R is the correct explanation of A
Both A and R are true but R is not a correct explanation of A
A is true but R is false
A is false but R is true

Discuss Question

Answer: Option D. -> A is false but R is true
:
D
Option:(d)

Question 70. Assertion (A): In a motion picture, usually 24 frames are projected every second over the whole length of the film.
Reason (R): An image formed on the retina of eye persists for about 0.1s after the removal of stimulus.
Codes