Pearson Edexcel International GCSE (9–1) · PHYSICS · Chapter
Light and Sound
70 practice questions
Topics covered
Practice questions
31–40 of 70
Question 31
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 32
1 mark · Easy
Answer and see the solution →Name the two types of glass that make up an optical fibre.
Question 33
1 mark · Easy
Answer and check →What property must the core of an optical fibre have compared to the cladding to allow total internal reflection?
- A.The core must have a higher refractive index than the cladding.
- B.The core must have a lower refractive index than the cladding.
- C.Both core and cladding must have the same refractive index.
- D.The cladding must be made of plastic.
Question 34
2 marks · Easy
Answer and see the solution →Explain why light is able to travel through a curved optical fibre without escaping.
Question 35
2 marks · Easy
Answer and see the solution →The diagram below represents a section through an optical fibre.
Optical fibre cross-section (a)[2 marks]Label A and B on the diagram as 'core' or 'cladding'.
Question 36
3 marks · Easy
Answer and see the solution →An engineer uses optical fibres to inspect the inside of a jet engine.
(a)[2 marks]State two reasons why using an optical fibre is useful in this situation.
(b)[1 mark]Explain how light travels from the entrance to the exit of the fibre.
Question 37
1 mark · Easy
Answer and check →Which statement best describes how light travels along an optical fibre?
- A.Light is refracted at the core–cladding boundary.
- B.Light is totally internally reflected at the core–cladding boundary.
- C.Light is absorbed by the core then re-emitted.
- D.Light bounces off the fibre's outer surface due to diffraction.
Question 38
2 marks · Easy
Answer and see the solution →State two different applications for optical fibres. For each, give a reason why optical fibres are a suitable choice.
Question 39
2 marks · Easy
Answer and see the solution →The table shows the refractive indices for different parts of an optical fibre:
Part of fibre Refractive index Core 1.52 Cladding 1.48 State which part ensures total internal reflection occurs, and explain your answer.
Question 40
2 marks · Normal
Answer and see the solution →Describe the main structure of an optical fibre. Name the two main parts and their roles.