Communication System (AIIMS Physics): Questions 6 - 9 of 12

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Question number: 6

» Communication System » Bandwidth of Transmission Medium

Appeared in Year: 2003

Assertion-Reason▾

Assertion (Ꭺ)

Microwave communication is preferred over optical communication.

Reason (Ꭱ)

Microwaves provide large number of channels and band width compared to optical signals.

Choices

Choice (4) Response

a.

Both Ꭺ and Ꭱ are false

b.

Both Ꭺ and Ꭱ are true and Ꭱ is the correct explanation of Ꭺ

c.

Both Ꭺ and Ꭱ are true but Ꭱ is NOT the correct explanation of Ꭺ

d.

Ꭺ is false but Ꭱ is true

Question number: 7

» Communication System » Sky and Space Wave Propagation

Appeared in Year: 2005

Assertion-Reason▾

Assertion (Ꭺ)

Television signals are received through sky-wave propagation.

Reason (Ꭱ)

The ionosphere reflects electromagnetic waves of frequencies greater than a certain critical frequency.

Choices

Choice (4) Response

a.

Ꭺ is true but Ꭱ is false

b.

Both Ꭺ and Ꭱ are false

c.

Both Ꭺ and Ꭱ are true but Ꭱ is NOT the correct explanation of Ꭺ

d.

Both Ꭺ and Ꭱ are true and Ꭱ is the correct explanation of Ꭺ

Question number: 8

» Communication System » Sky and Space Wave Propagation

MCQ▾

Question

For sky wave propagation of a 18 MHz signal, what should be the minimum electron density in ionosphere –

Choices

Choice (4) Response

a.

4×1012m3

b.

2×1022m3

c.

9×1014m3

d.

3×106m3

Question number: 9

» Communication System » Sky and Space Wave Propagation

MCQ▾

Question

In short wave communication waves of which of the following frequencies will be reflected back by the ionosphere layer having electron density 1018 per m3?

Choices

Choice (4) Response

a.

12 GHz

b.

9 GHz

c.

15 GHz

d.

3 GHz

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