3.2.2. Refraction of light
A subsection of Physics, 5054, through 3. Waves
Listing 10 of 64 questions
Use shows part of an optical fibre. P glass Q R The ray PQ undergoes total internal reflection in the optical fibre. On , continue the path of ray PQ until it reaches end R. Explain what is meant by total internal reflection. Optical fibres are cheaper and lighter than copper wires. State one other advantage of using optical fibres rather than copper wires for telephone communications. The light in the optical fibre is travelling at a speed of 2.1 × 108 m / s and has a wavelength of 6.4 × 10–7 m. Calculate the frequency of the light. frequency =
5054_s07_qp_2
THEORY
2007
Paper 2, Variant 0
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shows a man in a room looking into a mirror, as viewed from above. A mirror B The man can see an image of part of the wall AB in the mirror. Point C is the point on the wall closest to A that the man can see by reflection in the mirror. This point is not marked on . On , find point C and draw a ray of light from C which enables the man to see the image of C. On the ray that you have drawn on , label the angle of incidence i and the angle of reflection r. One characteristic of the image formed by the mirror is that it is virtual. 1. Explain what is meant by a virtual image. 2. State one other characteristic of an image formed by a plane mirror. Light travels along optical fibres by total internal reflection. State two differences between total internal reflection and reflection in a mirror. 1. 2. The critical angle for light travelling from the material of the fibre to air is 44°. Calculate the refractive index of the material in the fibre. refractive index = Light enters the optical fibre from air with an angle of incidence of 50°. Calculate the angle of refraction. angle of refraction = Optical fibres are used in telecommunications to send large amounts of data. Pulses of light travel at almost the same speed along a fibre as electrical pulses travel along a metal wire. State two advantages of using optical fibres rather than wires for transmitting data. 1. 2.
5054_s17_qp_22
THEORY
2017
Paper 2, Variant 2
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Questions Discovered
64