Pearson Edexcel International GCSE (9–1) · PHYSICS · Section
Total Internal Reflection
15 practice questions
Practice questions
1–10 of 15
Question 1
1 mark · Easy
Answer and see the solution →State what is meant by the term ‘critical angle’ when referring to light travelling from glass into air.
Question 2
3 marks · Easy
Answer and see the solution →A ray of light travels from a type of glass (refractive index 1.62) into air.
(a)[1 mark]Write down the equation linking the critical angle and the refractive index of the glass.
(b)[2 marks]Calculate the value of the critical angle, to 2 decimal places.
Question 3
1 mark · Easy
Answer and check →Which of the following conditions must be met for total internal reflection to occur at a glass–air boundary?
- A.The angle of incidence must be less than the critical angle and light travels from glass to air.
- B.The angle of incidence must equal the critical angle and light travels from air to glass.
- C.The angle of incidence must be greater than the critical angle and light travels from glass into air.
- D.The angle of incidence must be greater than the critical angle and light travels from air into glass.
Question 4
2 marks · Easy
Answer and see the solution →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.
Question 5
2 marks · Easy
Answer and see the solution →Explain why total internal reflection does not occur when light travels from air into glass, even if the angle of incidence is large.
Question 6
3 marks · Easy
Answer and see the solution →Optical fibres are used to carry communication signals as pulses of light.
(a)[1 mark]State the role of total internal reflection in an optical fibre.
(b)[2 marks]Explain, using the idea of critical angle, how the light pulse remains inside the fibre.
Question 7
1 mark · Easy
Answer and see the solution →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.
Question 8
3 marks · Easy
Answer and see the solution →A triangular glass prism is used in a periscope. The refractive index of the glass is 1.50.
(a)[2 marks]Calculate the critical angle for light inside this prism. Give your answer to 2 decimal places.
(b)[1 mark]Explain why light striking the prism face at 45° is totally internally reflected.
Question 9
5 marks · Normal
Answer and see the solution →A student uses a prism made from glass with refractive index 1.52. She shines a ray of light at 49° to the normal onto the surface between glass and air.
(a)[2 marks]Calculate the critical angle for this glass–air boundary. Give your answer to 1 decimal place.
(b)[3 marks]Will the ray undergo total internal reflection at the boundary? Explain your answer with a calculation or comparison.
Question 10
2 marks · Normal
Answer and see the solution →Prisms are often used in periscopes instead of mirrors. State one advantage of using prisms over mirrors and explain why this is beneficial.