ethyl alcohol n = 1.36
22
water n = 1.33
REFRACTION OF LIGHT
2. Benzene has an index of refraction of 1.50. a) find the speed of light in Benzene b) Find the critical angle for light moving from
benzene into water.
3. The wavelength of sodium light in air is 589 nm. Find its wavelength in ethyl alcohol.
4. A light ray in air is incident on a water surface at an angle of 30.0° with respect to the normal surface. What is the angle of the
refracted ray relative to the normal to the surface?
5. An underwater swimmer observes that a beam of sunlight in the water makes an angle of 31.0° with the vertical. Assuming the
surface of the water is level and horizontal, determine the beam’s angle as it enters the water.
6. A light ray initially in water enters a transparent substance at an angle of 37.0° with respect to the normal, and the transmitted
ray is refracted at an angle of 25.0°. Calculate the speed of light in the transparent substance.
8. How far does a beam of light travel in water in the same time it takes it to travel 10.0 m in glass of index of refraction 1.50?
9. A piece of glass with an index of refraction of 1.52 is in the shape of an equilateral
triangle. A beam of light initially in air and traveling parallel to the horizontal base of the
triangle enters one side of the glass triangle. What is the angle between the ray and the
horizontal after it emerges from the triangle?
Θ
10. A beam of light is incident at an angle of 37.0° on the surface of a block of transparent material. The angle of refraction is found
to be 25.0°. What is the speed of light in the material?
11. The Sun is 10.0° above the horizon. If you are swimming beneath the surface of a pool of water, at what angle above the horizon
does the Sun appear to be?
12. A spear fisherman stands on the shore and spots a fish underwater. When he throws his spear, should he aim directly at the fish,
or should he aim slightly above it or slightly below it? Explain.
13. The index of refraction of a certain type of glass is 1.516 for a specific wavelength of red light and 1.524 for a specific
wavelength of violet light. If light composed of those two wavelengths is incident from air on that glass at an angle of 45o, what
is the angle between the refracted red ray and the refracted violet ray?
n!
c
v
c = 3.00 x 108 m/s
n 1sin!1 = n 2 sin!2
v = fλ
sin" c =
Answers:
2) a) v = 2.00 × 108 m/s b) 62.5o
5) θ1 = 43.4°
10) v = 2.11 × 108 m/s
3) λmedium = 433 nm
6) v = 1.58 × 108 m/s
11) 42.4°
4) θ = 22.0°.
8) dw = 11.3 m
12) below
13) 0.158o
!
9) 53.3o
n2
n1