3.2.2. Refraction of light
A subsection of Physics, 5054, through 3. Waves
Listing 10 of 64 questions
State the speed of light in air. shows a ray of blue light passing from air into a glass block and refracting at the surface. glass block blue light (not to scale) As the light enters the glass, state what happens to 1. the speed of the light, 2. the frequency of the light, 3. the wavelength of the light. On , mark and label the angle of incidence i and the angle of refraction r. The refractive index of glass for blue light is 1.5. A ray of blue light strikes the surface of a glass block at an angle of incidence of 89°. Calculate the angle of refraction of the light in the block. angle of refraction = Explain why the angle of refraction of blue light in glass is always less than 45°. Blue light, travelling in air, strikes the side of a different glass block and continues in the same direction as it enters the glass block. shows the ray of light and the shape of the glass block. The critical angle for this glass is 42°. 45° blue light Explain why the light continues in the same direction as it enters the glass block. On , complete the path of the light until it leaves the glass.
5054_w14_qp_22
THEORY
2014
Paper 2, Variant 2
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A laser produces a beam of red light. The red light from the laser has a frequency of 4.3 × 1014 Hz. State the speed of light in air. Calculate the wavelength of this red light in air. wavelength = Red light from the laser strikes one side of a glass prism at an angle of incidence i. The light refracts towards the normal as it enters the prism. shows the prism, the light and a screen. 30° 30° i θ screen laser red light (not to scale) State what happens to the speed of light as it enters the glass. The refractive index of the glass is 1.5. The angle of refraction in the glass, where the light enters the prism, is 30°. Calculate the angle of incidence i. i = The light then passes back into the air and strikes the front of the white screen, as shown in . Calculate θ, the angle between the ray in air and the side of the prism. θ = The laser in is replaced with a filament lamp and a slit, as shown in . screen filament lamp white light (not to scale) A ray of white light now strikes the prism. On , draw what happens to the light as it passes through the prism and strikes the screen. Describe what is seen on the screen. In addition to visible light, the filament lamp also emits some infra-red radiation. This infra-red radiation is able to pass through glass. 1. On the screen in , mark an X to indicate a place where infra-red radiation strikes the screen. 2. Infra-red radiation is often detected by using a sensitive thermometer with a bulb that has been painted black. Explain why the blackened bulb makes the thermometer a good detector of infra- red radiation. Explain the role played by infra-red radiation in intruder alarms.
5054_w16_qp_22
THEORY
2016
Paper 2, Variant 2
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Questions Discovered
64