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Pearson Edexcel International GCSE (9–1) · PHYSICS · Section

Total Internal Reflection

15 practice questions

Start practising (8 questions)

Practice questions

1–8 of 8 · Easy

  1. Question 1

    1 mark · Easy

    State what is meant by the term ‘critical angle’ when referring to light travelling from glass into air.

    Answer and see the solution →

  2. Question 2

    3 marks · Easy

    A ray of light travels from a type of glass (refractive index 1.62) into air.

    (a)

    Write down the equation linking the critical angle and the refractive index of the glass.

    [1 mark]
    (b)

    Calculate the value of the critical angle, to 2 decimal places.

    [2 marks]
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  3. Question 3

    1 mark · Easy

    Which of the following conditions must be met for total internal reflection to occur at a glass–air boundary?

    1. A.The angle of incidence must be less than the critical angle and light travels from glass to air.
    2. B.The angle of incidence must equal the critical angle and light travels from air to glass.
    3. C.The angle of incidence must be greater than the critical angle and light travels from glass into air.
    4. D.The angle of incidence must be greater than the critical angle and light travels from air into glass.
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  4. Question 4

    2 marks · Easy

    Angles measured for a glass–air interface
    Angle of incidence (i)Angle of refraction (r)
    30°19°
    40°27°
    42°90°

    Using the table above, identify the critical angle for this glass–air boundary and explain how you know.

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  5. Question 5

    2 marks · Easy

    Explain why total internal reflection does not occur when light travels from air into glass, even if the angle of incidence is large.

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  6. Question 6

    3 marks · Easy

    Optical fibres are used to carry communication signals as pulses of light.

    (a)

    State the role of total internal reflection in an optical fibre.

    [1 mark]
    (b)

    Explain, using the idea of critical angle, how the light pulse remains inside the fibre.

    [2 marks]
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  7. Question 7

    1 mark · Easy

    Complete the following sentence: A ray of light passing from glass into air will be totally internally reflected if the angle of incidence is _______ the critical angle.

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  8. Question 8

    3 marks · Easy

    A triangular glass prism is used in a periscope. The refractive index of the glass is 1.50.

    (a)

    Calculate the critical angle for light inside this prism. Give your answer to 2 decimal places.

    [2 marks]
    (b)

    Explain why light striking the prism face at 45° is totally internally reflected.

    [1 mark]
    Answer and see the solution →