# Electromagnetic Waves (NEET (NTA)-National Eligibility cum Entrance Test (Medical) Physics): Questions 16 - 22 of 31

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## Question number: 16

» Electromagnetic Waves » Electromagnetic Waves & Characteristics

MCQ▾

### Question

Electromagnetic waves travel in a medium with a speed of 2 x 10 8 m/s. The relative permeability of the medium is 1. What is the relative permittivity of the medium?

### Choices

Choice (4) Response

a.

-0.25

b.

2.25

c.

3.25

d.

1.25

## Question number: 17

» Electromagnetic Waves » Electromagnetic Waves & Characteristics

Assertion-Reason▾

### Assertion (Ꭺ)

The electromagnetic waves of shorter wavelength can travel longer distances on earth’s surface than those of longer wavelengths.

### Reason (Ꭱ)

Shorter the wavelength, the larger is the velocity of wave propagation.

### Choices

Choice (4) Response

a.

Ꭺ is true but Ꭱ is false

b.

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

c.

Both Ꭺ and Ꭱ are false

d.

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

## Question number: 18

» Electromagnetic Waves » Electromagnetic Waves & Characteristics

MCQ▾

### Question

Unit of expression µ 0ϵ 0 is,

### Choices

Choice (4) Response

a.

m/s

b.

s/m

c.

s 2 /m 2

d.

m 2 /s 2

## Passage

Read the passage given below and answer the questions that follow:

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

## Question number: 19 (1 of 3 Based on Passage) Show Passage

» Electromagnetic Waves » Electromagnetic Spectrum » Radio Waves

MCQ▾

### Question

The maximum useable frequency

### Choices

Choice (4) Response

a.

4.57 x 10 9 Hz

b.

4.57 x l0 6 Hz

c.

3.17 x l0 6 Hz

d.

3.17 x 10 8 Hz

## Question number: 20 (2 of 3 Based on Passage) Show Passage

» Electromagnetic Waves » Electromagnetic Spectrum » Radio Waves

MCQ▾

### Question

The angle of incidence of this layer

### Choices

Choice (4) Response

a.

34.5°

b.

25.2°

c.

31.6°

d.

40°

## Question number: 21 (3 of 3 Based on Passage) Show Passage

» Electromagnetic Waves » Electromagnetic Spectrum » Radio Waves

MCQ▾

### Question

The critical frequency of the layer

### Choices

Choice (4) Response

a.

2.7 x 10 6 Hz

b.

4.7x 10 6 Hz

c.

2.7 x 10 5 Hz

d.

4.8 x 10 5 Hz

## Question number: 22

» Electromagnetic Waves » Electromagnetic Waves & Characteristics

MCQ▾

### Question

Which of the following are electromagnetic waves?

(1) Cosmic rays (2) Gamma rays

(3) X-rays (4) β-rays

Select the correct answers and mark it according to the following codes:

Codes:

### Choices

Choice (4) Response

a.

1 and 2 are correct

b.

1 and 3 are correct

c.

1,2 and 3 are correct

d.

2 and 4 are correct

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