Electromagnetic Waves

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Question

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Question 1 :

Wave which cannot travel in vacuum is:

1. X-rays
2. infrasonic
3. ultraviolet
4. radio waves
Answer
4722

Question 2 :

Particle nature and wave nature of electromagnetic waves and electrons can be shown by

1. electron has small mass, deflected by the metal sheet
2. X-ray is diffracted, reflected by thick metal sheet
3. light is refracted and diffracted
4. light is polarised and refracted.
Answer
4723

Question 3 :

The velocity of electromagnetic waves in free space is 3 x 108 m/sec. The frequency of a radio wave of wave length 150 m, is

1. 20 kHz
2. 45 MHz
3. 2 kHz
4. 2 MHz.
Answer
4724

Question 4 :

Read the Assertion and Reason carefully to mark the correct option out of the options given below:
Assertion : A pulsar is a source of radiowaves that vary in intensity at regular intervals.
Reason: A pulsar is a rotating neutron star.

1. If both assertion and reason are true and the reason is the correct explanation of the assertion.
2. If both assertion and reason are true but reason is not the correct explanation of the assertion.
3. If assertion is true but reason is false.
4. If the assertion and reason both are false.
5. If assertion is false but reason is true.
Answer
4725

Question 5 :

Read the Assertion and Reason carefully to mark the correct option out of the options given below:
Assertion : Infrared rays are used in fog.
Reason : The wavelength of infrared rays are smaller.

1. If both assertion and reason are true and the reason is the correct explanation of the assertion.
2. If both assertion and reason are true but reason is not the correct explanation of the assertion.
3. If assertion is true but reason is false.
4. If the assertion and reason both are false.
5. If assertion is false but reason is true.
Answer
4726