# Electromagnetic Waves (NEET Physics): Questions 21 - 26 of 31

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## Passage

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: 21 (3 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: 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

## Question number: 23

» Electromagnetic Waves » Electromagnetic Waves & Characteristics

MCQ▾

### Question

A light beam travelling in the X-direction is described by the electric field

. An electron is constrained to move along the Y-direction with a speed of 2.0 x 10 7 m/s. Find the maximum magnetic force (in N) on the electron.

### Choices

Choice (4) Response

a.

3.2 x 10 -18

b.

5.1 x 10 -16

c.

6.5 x 10 -11

d.

7.8 x 10 -12

## Question number: 24

» Electromagnetic Waves » Electromagnetic Spectrum » Visible

MCQ▾

### Question

The range of wavelength of the visible light is

### Choices

Choice (4) Response

a.

4, 000 Å to 8, 000 Å

b.

8, 000 Å to 10, 000 Å

c.

10 Å to 100 Å

d.

10, 000 Å to 15000 Å

## Question number: 25

» Electromagnetic Waves » Electromagnetic Waves & Characteristics

MCQ▾

### Question

A wave is propagating in a medium of dielectric constant 2 and relative magnetic permeability 50. The wave impedance of such a medium is

### Choices

Choice (4) Response

a.

1883 Ω

b.

376.6Ω

c.

3776 Ω

d.

## Question number: 26

» Electromagnetic Waves » Applications of Electromagnetic Waves

MCQ▾

### Question

Which of the following statements are true?

(1) Photographic plates are sensitive to ultraviolet rays.

(2) Photographic plates can be made sensitive to infrared rays.

(3) Infrared rays are emitted by hot objects.

(4) Infrared photon has more energy than the photon of visible light.

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, 2 and 3 are correct

c.

2 and 4 are correct

d.

1 and 3 are correct

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