Pearson Edexcel International GCSE (9–1) · PHYSICS · Unit
Waves
356 practice questions
Topics covered
Practice questions
341–350 of 356
Question 341
5 marks · Normal
Answer and see the solution →Optical fibres use total internal reflection to transmit light signals long distances, which is similar to how prisms are used in periscopes.
(a)[2 marks]Explain why total internal reflection occurs inside an optical fibre and draw a labelled diagram to illustrate it.
(b)[2 marks]State one medical and one communication use of optical fibres.
(c)[1 mark]A certain type of glass has a refractive index of 1.56. Calculate its critical angle for total internal reflection.
Question 342
6 marks · Normal
Answer and see the solution →When a ray of light passes from air into glass, part of the light is refracted and part is reflected. Sounds can also be reflected by surfaces.
(a)[2 marks]Complete the ray diagram below for a ray passing from air into a glass block and emerging on the other side. Draw the path through the block, marking the normals, angles of incidence and refraction.
(b)[2 marks]A ship uses echo sounding (sonar) to measure ocean depth. If the sound pulse returns after 3.0 s and the speed of sound in seawater is 1500 m/s, calculate the depth of the ocean.
(c)[2 marks]Compare the laws of reflection for light and sound. Give one difference in how each wave behaves when it meets a surface.
Question 343
5 marks · Normal
Answer and see the solution →Sound and light both travel as waves but have different properties.
(a)[2 marks]State whether light and sound are transverse or longitudinal waves respectively. Give one piece of evidence for your answer in each case.
(b)[2 marks]A sound wave has a frequency of 440 Hz and travels at 340 m/s in air. Calculate its wavelength.
(c)[1 mark]State the range of frequencies the average person can hear. Describe how loudness and pitch are represented on an oscilloscope trace of a sound wave.
Question 344
5 marks · Normal
Answer and see the solution →The diagram below shows a prism, like those used in binoculars, and a glass block. Both rely on total internal reflection.
(a)[2 marks]Describe and explain what happens to a ray of light inside a prism when it strikes the surface at an angle greater than the critical angle. Draw a labelled diagram to support your answer.
(b)[2 marks]Calculate the angle of refraction if a ray of light enters glass from air at 35° and the refractive index of glass is 1.52.
(c)[1 mark]Binoculars use prisms for total internal reflection, but sound waves cannot be 'bent' this way. Suggest one reason for this difference.
Question 345
4 marks · Easy
Answer and see the solution →Look at the diagram below showing a ray of light travelling from air into a glass block at 30° to the normal.
Ray of light entering glass at 30° to normal. (a)[1 mark]State the meaning of 'refraction'.
(b)[1 mark]Draw an arrow on the diagram to show the path of the refracted ray inside the glass block, bending towards the normal.
(c)[2 marks]Explain why the refracted ray bends towards the normal.
Question 346
4 marks · Easy
Answer and see the solution →A student investigates water waves in a ripple tank and observes the behaviour of a ray of light travelling from air into glass.
(a)[2 marks]Describe what is meant by the amplitude and wavelength of a wave.
(b)[1 mark]State what happens to the speed of a ray of light as it passes from air into glass.
(c)[1 mark]Give one unit, other than the metre, used for measuring waves.
Question 347
4 marks · Easy
Answer and see the solution →A sound wave travels through air at a speed of 340 m/s.
(a)[2 marks]If the frequency of the sound wave is 680 Hz, calculate its wavelength.
(b)[1 mark]Write down the equation you used for this calculation.
(c)[1 mark]Give one feature of a sound wave you can see displayed on an oscilloscope.
Question 348
4 marks · Easy
Answer and see the solution →A ray of light passes from air into water at an angle of incidence of 35°. The angle of refraction inside the water is measured as 22°.
(a)[2 marks]Calculate the refractive index of water. Show your working clearly.
(b)[1 mark]Write down the equation relating angle of incidence and angle of refraction to refractive index.
(c)[1 mark]Explain, in terms of wave speed, why refraction occurs when light passes from air into water.
Question 349
4 marks · Easy
Answer and see the solution →A student is learning about wave properties with a slinky spring and a light ray box.
(a)[3 marks]State the unit for each of the following quantities:
Quantity Unit Angle Wave frequency Wavelength (b)[1 mark]Explain what is meant by the term 'wavefront'.
Question 350
4 marks · Easy
Answer and see the solution →The diagram below shows both a light ray and a sound wave being used in communication and medical technology.
(a)[2 marks]Name the type of wave (longitudinal or transverse) for each of the following:
Wave Type Light wave Sound wave (b)[2 marks]State one use of optical fibres and one use of sound waves in medicine.