3.2.2. Refraction of light
A subsection of Physics, 5054, through 3. Waves
Listing 10 of 64 questions
shows a young boy lying on his back on the bottom of a swimming pool. He is holding his breath and his eyes are open. A red light is positioned on the ground at Q. At first the boy’s head is touching the pool wall. He notices that, as he slides away from the pool wall, his eye reaches a point P where he first sees the light at Q. shows the boy in this position. eye P Q air water pool wall red light On , draw the ray of light travelling from Q to P. Mark the critical angle for light in water and label it C. Explain why the boy is unable to see the red light at Q when his eye is closer to the pool wall than P. The critical angle is 49°. Calculate the refractive index of water. refractive index = The red light is now replaced with a blue light. State the effect of this on the wavelength of the light in the air. A small, very brightly illuminated display is located at the back of a projector. The projector lens produces an inverted and magnified image of the display on a white classroom wall. is a scale diagram showing the position and size of both the display and the image on the wall. R is a point on the display. display display 1 cm 1 cm scale: 1 cm represents 12 cm R image on the wall image on the wall The image is inverted and magnified. State two other properties of the image. 1. 2. On , draw the straight-line ray from R to the image. On , draw a vertical line representing the lens and label it L. A second ray from R to the image passes through a focal point (principal focus) of the lens. On , draw this ray and use it to mark this focal point. Label this focal point F. Determine the focal length of the lens. focal length =
5054_w10_qp_21
THEORY
2010
Paper 2, Variant 1
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10 A student goes for a walk in the mountains. During a storm, she sees lightning strike a hillside in the distance. Several seconds later, she hears the thunder caused by the lightning. Explain why she hears the thunder several seconds after she sees the lightning. The student knows the distance to the hillside. She waits for lightning to strike the hillside again. Describe how she can determine a value for the speed of sound in air. After the storm, the student sees a rainbow. State the speed of light in air. speed = Calculate the wavelength in air of light of frequency 7.5 × 1014 Hz. wavelength = State the colours of the spectrum in order of increasing wavelength. In the laboratory, the student sends blue light into a glass prism placed on a sheet of paper. The arrangement is shown in . 45° blue light The blue light enters the prism with an angle of incidence of 45°. On , mark the angle of refraction in the glass and label it r. The student wishes to determine the angle of refraction. On the sheet of paper, she draws the path the ray takes in the glass. Describe how she could do this. 1. State the formula that relates the angle of incidence i, the angle of refraction r and the refractive index n. 2. The angle of refraction in the glass is 28°. Calculate the refractive index of the glass. refractive index = The student sends a ray of red light to the glass prism along the same path as the blue light. On , mark the path taken by the red light after it enters the prism.
5054_w13_qp_21
THEORY
2013
Paper 2, Variant 1
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Questions Discovered
64