# Communication System-Sky and Space Wave Propagation (NEET (National Eligibility cum Medical Entrance Test) Physics): Questions 4 - 7 of 7

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## Question number: 4

» Communication System » Sky and Space Wave Propagation

MCQ▾

### Question

Maximum usable frequency (MUF) in F-region layer is x, when the critical frequency is 55 MHz and the angle of incidence is 60°. Then x is (cos 70° = 0.34)

### Choices

Choice (4) Response

a.

120 MHz

b.

110 MHz

c.

109 MHz

d.

150 MHz

## Passage

The electron density of a layer of ionosphere at a height 150 km from the earth’s surface is 9 ⨯ 10 9 per m 3. For the sky transmission from this layer up to a range of 250 km,

## Question number: 5 (1 of 1 Based on Passage) Show Passage

» Communication System » Sky and Space Wave Propagation

MCQ▾

### Question

The critical frequency of the layer is

### Choices

Choice (4) Response

a.

2.7 Hz

b.

2 Hz

c.

2.7 MHz

d.

2.78 kHz

## Question number: 6

» Communication System » Sky and Space Wave Propagation

MCQ▾

### Question

Maximum usable frequency (MUF) in F-region layer is x, when the critical frequency is 60 MHz and the angle of incidence is 70°. Then x is (cos 70° = 0.34)

### Choices

Choice (4) Response

a.

175 MHz

b.

190 MHz

c.

150 MHz

d.

170 MHz

## Question number: 7

» Communication System » Sky and Space Wave Propagation

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.

f Page