Pearson Edexcel International GCSE (9–1) · PHYSICS · Chapter
Light and Sound
70 practice questions
Topics covered
Practice questions
11–20 of 36 · Normal
Question 11
3 marks · Normal
Answer and see the solution →Describe an experiment using a semi-circular glass block and a ray box to determine the critical angle of glass. State the steps you would take and the measurements you would make.
Question 12
1 mark · Normal
Answer and check →Which statement correctly describes total internal reflection in the context of light travelling from glass into air?
- A.It occurs when the angle of incidence is less than the critical angle.
- B.It occurs only when the angle of reflection equals the critical angle.
- C.It occurs when the angle of incidence is greater than the critical angle.
- D.It occurs for any angle when light passes from air into glass.
Question 13
3 marks · Normal
Answer and see the solution →A glass block has a refractive index of 1.48. Calculate: a) The value of sin of the critical angle. b) The value of the critical angle itself (to 2 decimal places).
Question 14
3 marks · Normal
Answer and see the solution →A laser beam is sent into an optical fibre made of glass surrounded by air. Explain why the light remains trapped inside the fibre when it travels around bends.
Question 15
4 marks · Normal
Answer and see the solution →A beam of light travels from water (refractive index 1.33) into air.
(a)[3 marks]Calculate the critical angle for the water–air boundary. Give your answer to 1 decimal place.
(b)[1 mark]Would total internal reflection occur if the angle of incidence in water is 48°? Show your working.
Question 16
2 marks · Normal
Answer and see the solution →Describe the main structure of an optical fibre. Name the two main parts and their roles.
Question 17
1 mark · Normal
Answer and check →Which of the following is a correct statement about total internal reflection in an optical fibre?
- A.It can occur only when light travels from a region of lower to higher refractive index.
- B.It occurs whenever light enters an optical fibre, regardless of angle.
- C.It keeps light inside the core of the fibre if the angle is greater than the critical angle.
- D.It allows light to escape from the sides of the fibre easily.
Question 18
3 marks · Normal
Answer and see the solution →Explain how total internal reflection inside an optical fibre ensures that light follows the path of the fibre even if it bends.
Question 19
2 marks · Normal
Answer and see the solution →A telecommunications company wants to replace copper wires with optical fibres. Give two reasons, based on physics, why optical fibres are better for transmitting signals over long distances.
Question 20
4 marks · Normal
Answer and see the solution →The diagram below shows a simplified optical fibre.
Simplified cross-section of an optical fibre. (a)[1 mark]Label the core and cladding on the diagram.
(b)[2 marks]Draw a path to show how light travels along the optical fibre, reflecting from the core–cladding boundary.
(c)[1 mark]Explain why the light remains in the core as it travels.