Question 1

Which of the following is correct when total internal reflection occurs?

  A  

the angle of incidence is less than the critical angle

  B  

the light meets an optically less dense medium


  C  

the light enters a medium with a higher refractive index

  D  

the angles that the incident and refracted rays make with the normal are the same

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Question 2

What is the speed of light in glass of refractive index 1.42?

  A  

4.26 × 107 m s–1

  B  

2.11 × 108 m s–1


  C  

3.00 × 108 m s–1


  D  

4.73 × 108 m s–1

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Question 3

Monochromatic light may be characterised by its speed, frequency and wavelength. Which of the following quantities change when monochromatic light passes from air into glass?

  A  

speed only

  B  

speed and wavelength only


  C  

speed and frequency only

  D  

wavelength and frequency only

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Question 4

Which characteristics of monochromatic light change when the light passes from air into glass?

  A  

speed, wavelength and frequency

  B  

speed and frequency only


  C  

speed and wavelength only


  D  

wavelength and frequency only

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Question 5

A ray of light is incident on a glass–air boundary of a rectangular block as shown.

The refractive index of this glass is 1.5

The refractive index of air is 1.0

The angle of incidence of the light at the first glass–air boundary is 44°

What is the path of the ray of light?

  A  
  B  
  C  
  D  

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Question 6

An electromagnetic wave enters a fibre-optic cable from air. On entering the cable, the wave slows down to three-fifths of its original speed.

What is the refractive index of the core of the fibre-optic cable?

  A  

0.67

  B  

1.33

  C  

1.50

  D  

1.67

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Question 7

The diagram shows a ray of light travelling in air and incident on a glass block of refractive index 1.5


What is the angle of refraction in the glass?

  A  

22.5°

  B  

23.3°

  C  

33.1°

  D  

59.4°

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Question 8

The speed of light in air is 3.0 × 108m s–1 and the speed of light in glass is 2.0 × 108m s–1. A ray of monochromatic light in glass strikes the glass-air boundary at an angle of 80° to the boundary.

What is the angle made to the normal by the ray of light leaving the boundary?


  A  

6.6°

  B  

15°


  C  

41°


  D  

49°


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Question 9

The table shows the refractive index n of four transparent materials A, B, C and D.

Which material has the smallest critical angle?

  A  
  B  
  C  
  D  

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