# Communication System (AIIMS (All India Institute of Medical Sciences) Physics): Questions 1 - 5 of 12

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## Question number: 1

» Communication System » Sky and Space Wave Propagation

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Appeared in Year: 2005

MCQ▾

### Question

For sky wave propagation of a 10 MHz signal, what should be the minimum electron density in ionosphere –

### Choices

Choice (4)Response

a.

b.

c.

d.

## Question number: 2

» Communication System » Amplitude and Frequency Modulation

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Appeared in Year: 2006

MCQ▾

### Question

Given below is a circuit diagram of an AM demodulator

For good demodulation of AM signal of carrier frequency f, the value of RC should be –

### Choices

Choice (4)Response

a.

b.

c.

d.

## Question number: 3

» Communication System » Propagation of Electromagnetic Waves in the Atmosphere

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Appeared in Year: 2003

MCQ▾

### Question

The maximum distance up to which TV transmission from a TV tower of height h can be received is proportional to –

### Choices

Choice (4)Response

a.

b.

c.

d.

## Question number: 4

» Communication System » Sky and Space Wave Propagation

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Appeared in Year: 2003

MCQ▾

### Question

In short wave communication waves of which of the following frequencies will be reflected back by the ionosphere layer having electron density 1011 per m3?

### Choices

Choice (4)Response

a.

10 MHz

b.

18 MHz

c.

2 MHz

d.

12 MHz

## Question number: 5

» Communication System » Propagation of Electromagnetic Waves in the Atmosphere

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Appeared in Year: 2006

Assertion-Reason▾

### Assertion (Ꭺ)

Electromagnetic waves with frequencies smaller than the critical frequency of ionosphere cannot be used for communication using sky wave propagation.

### Reason (Ꭱ)

The refractive index of the ionosphere becomes very high for frequencies higher than the critical frequency.

### 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.

Ꭺ is true but Ꭱ is false

d.

Ꭺ is false but Ꭱ is true

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