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A: At great heights from surface of eart...

A: At great heights from surface of earth and close to earth ionisation of air molecules is low. B: `EM` waves of frequencies beyond `30 MHz` penetrate ionosphere and escape.

A

both `A`and `B` are correct

B

both `A` and `B` are wrong

C

only `A` is correct

D

only `B` is correct

Text Solution

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The correct Answer is:
A
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NARAYNA-COMMUNICATION SYSTEM-C.U.Q
  1. Frequencies in the UHF range normally propagate by means of:

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  2. When a sky wave is reflected onto the ground

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  3. The electromagnetic waves of frequency 2 MHz and 30 MHz are

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  4. Among the follwing frequencies one will be suitable for beyond-the hor...

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  5. Among the follwing , the waves which can penetrate the ionosphere are

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  6. A: At great heights from surface of earth and close to earth ionisatio...

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  7. Through which mode of propagation, the radio waves can be sent from on...

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  8. The frequency at which communication will not be reliable is

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  9. The frequency above which radiation of electrical energy is practical ...

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  10. The ratio waves of frequency 300 MHz to 3000 MHz belong to

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  11. Coaxial cable is an example of

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  12. Optical fibre communication is generally preferred over general commun...

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  13. the attenution in optical fibre is mainly due to

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  14. Consider telecommunication through optical fibres. Which of the follow...

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  15. The phenomenon by which light travels in an optical fibres is

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  16. Laser light is considered to be coherent because it consists of

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  17. In which of the following remote sensing technique is not used?

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  18. The question has statement - 1 and statement - 2 Of the four choices ...

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  19. Choose the correct statement.

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  20. Figure shows a block diagram of a transmitter. Identify the boxes X an...

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