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(A): Sky wave signal are used for long d...

(A): Sky wave signal are used for long distance radio communication. These signals are in general, less stable than ground wave signals.
(R): The state of ionosphere varies from hour to hour, day to day and season to season.

A

Both 'A' and 'R' are true and 'R' is the correct explanation of 'A'.

B

Both 'A' and 'R' are true and 'R' is not the correct explanation of 'A'.

C

A' is true abd 'R' false

D

A' is false and 'R' is false

Text Solution

Verified by Experts

The correct Answer is:
B
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AAKASH SERIES-COMMUNICATION SYSTEMS -Exercise - IB (Assertion (A) & Reason (R) Type Questions)
  1. (A) : The sky waves are not used in the transmission of television sig...

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  2. (A) : Television signals are propagated through space waves. (R) : ...

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  3. (A): Sky wave signal are used for long distance radio communication. T...

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  4. (A) : Short wave communication over long distance is not possible via ...

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  5. (A) : Optical communication is preferred to microwave communication ...

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  6. (A) : For TV broadcasting and medium wave band, surface wave propagati...

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  7. (A) : TV waves become attenuated with increasing distance. (R) : Th...

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  8. (A) : For long distance transmission of radio waves, short wave bands ...

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  9. (A) : Propagation of electromagnetic waves as microwaves is better tha...

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  10. (A) : The lectromagnetic waves of shorter wavelengths can travel long...

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  11. (A) : In case of frequency modulation, the frequency of the RF carrier...

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  12. (A) : Digital signals are preferred to analog signals for transmission...

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  13. (A) : A portable AM radio set must be kept horizontal to receive the s...

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  14. (A) : In point - to point communication mode communication takes place...

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  15. (A) : Range is the largest distance between a source and a destination...

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  16. (A) : For transmitting a signal, the antenna should have a size compa...

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  17. (A) : At frequencies above 40 MHz, communication is essentially limite...

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  18. (A) : Sky wave is reflected by ionosphere (R) : The reflected wave ...

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  19. (A) : Communication in UHF/VHF regions can be established by space wa...

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  20. (A) : In a communication system based on amplitude modulation the modu...

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