The principle of LASER action involves from Physics Communicatio

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 Multiple Choice QuestionsMultiple Choice Questions

71.

Assertion: In high latitudes one sees colourful curtains of light hanging down from high altitudes. 

Reason: The high energy charged particles from the are deflected to polar regions by the magnetic field of the earth.

  • if both assertion and reason are true and the reason is the correct explanation of the assertion

  • if both assertion and reason are true and the reason is not the correct explanation of the assertion

  • if assertion is true but reason is false

  • if both assertion and reason are false statements


72.

High-frequency waves are

  • affected by the solar cycle

  • reflected by D2 layer

  • absorbed by the F2

  • capable of use for long-distance communication on the moon


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73.

The principle of LASER action involves

  • amplification of particular frequency emitted by the system

  • population inversion

  • stimulated emission

  • All of the above


D.

All of the above


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74.

Through which mode of propagation, the radio waves can be sent from one place to another?

  • Ground wave propagation

  • Sky wave propagation

  • Space wave propagation

  • All of the above


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75.

The binary number 10111 is equivalent to the decimal number

  • 19

  • 31

  • 23

  • 22


76.

To write the decimal number 37 in binary, how many binary digits are required ?

  • 5

  • 6

  • 7

  • 4


77.

The decimal equivalent of the binary number (11010.101)2 is 

  • 9.625

  • 25.265

  • 26.625

  • 26.265


78.

The decimal number equivalent to a binary number 1011001 is

  • 13

  • 17

  • 89

  • 178


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