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The highest frequency of radiowaves whic...

The highest frequency of radiowaves which when sent at some angle towards the ionosphere , gets reflected from that and returns to the earth is called

A

critical frequency

B

maximum unusable

C

polarisation of waves

D

None of the above

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The correct Answer is:
B
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AAKASH SERIES-COMMUNICATION SYSTEM -LECTURE SHEET (LEVEL - I) (MAIN) (EXERCISE - IV) (Straight Objective & More than one Correct Answer Type Questions)
  1. The highest frequency of radiowaves which when sent at some angle towa...

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  2. Speed of electromagnetic waves is the same

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  3. In space communication, the information can be passed from one place t...

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  4. Which one of the following is correct ?

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  5. The space wave propagation is utilized in

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  6. Three waves A,B and C of frequencies 1600 KHz, 5MHz and 60 MHz, respec...

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  7. A transmitter transmits the message in original

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  8. A receiver reconstructs the original message after propagation through...

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  9. A 100m long antenna is mounted on a 500m tall building. The complex ca...

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  10. A diode detector is used to detect an amplitude modulated wave of 60% ...

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  11. The number of telephone conversations by a fibre of band width 40MHz, ...

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  12. Which of the following devices is full duplex?

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  13. Which of the following devices is half duplex ?

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  14. Which of the following statement is wrong?

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  15. Through which mode of propagation the radio waves can be sent from one...

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  16. The maximum peak to peak voltage of an AM wire is 24 mV and the minimu...

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  17. In a communication system, noise is most likely to affect the signal

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  18. The radio waves of frequency 300 MHz to 3000 MHz belong to

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  19. Match the column I with column II.

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  20. Match the following elements of column I with their property given in ...

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