Electromagnetic Waves  MCQs

MCQs of Electromagnetic Waves

Showing 71 to 80 out of 112 Questions
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71.
The value of μ0ε0-12 is _____ .
(a) 3 × 1010 ms-1
(b) 3 × 108 ms-1
(c) 3 × 108 kms-1
(d) 3 × 1010 mms-1
Answer:

Option (b)

72.
Light with an energy flux of 18 W cm-2 falls on a non - reflecting surface at normal incidence. If the surface has an area of 20 cm2, then the average force exerted on the surface during a 30 minute time is _____ N.
(a) 10-4
(b) 1.2 × 10-6
(c) 2.4 × 10-6
(d) 3.6 × 10-6
Answer:

Option (b)

73.
The sun delivers 103 W/m2 of electromagnetic flux to the earth's surface. The total power that is incident on a roof of dimensions 8 m × 20 m, will be _____ .
(a) 6.4 × 103 W
(b) 3.4 × 104 W
(c) 1.6 × 105 W
(d) Non of the above
Answer:

Option (c)

74.
In which part of earth's atmosphere is the ozone layer present ?
(a) troposphere
(b) stratosphere
(c) ionosphere
(d) mesosphere
Answer:

Option (b)

75.
Green house effect keeps the earth surface _____ .
(a) cold at night
(b) dusty and cold
(c) warm at night
(d) moist
Answer:

Option (c)

76.
Low lying clouds reflects back the _____ .
(a) ultraviolet radiations
(b) infrared radiations
(c) all radiations
(d) X - rays radiations
Answer:

Option (b)

77.
Which of the following is not an electromagnetic wave ?
(a) Sound waves
(b) Radar waves
(c) γ - rays
(d) X - rays
Answer:

Option (a)

78.
Cosmic rays are _____ .
(a) high energy radiations
(b) low energy radiations
(c) ultra high energy radiations
(d) very low energy radiation
Answer:

Option (a)

79.
The waves which cannot travel in vacuum are _____ .
(a) X - rays
(b) radio waves
(c) infrasonic waves
(d) ultraviolet waves
Answer:

Option (c)

80.
Frequency range of frequency modulated radio wave is _____ to _____ .
(a) 88 GHz to 108 GHz
(b) 88 Hz to 108 Hz
(c) 88 MHz to 108 MHz
(d) 88 KHz to 108 KHz
Answer:

Option (c)

Showing 71 to 80 out of 112 Questions
5 6 7 8 9 10