Index of Refraction



1)        The frequency of red light is 4.5 × 1014 Hz. What is its wavelength in a vacuum?




2)        Imagine a friend of yours is sitting comfortably, underwater, on the bottom of a swimming pool. If you are looking directly into your friend’s eyes, is your friend looking directly into yours?




3)        You’re walking along the shore of a lake, terribly hungry, and you see a fish swimming in shallow water. If you try to spear the fish, should you aim directly at the image of the fish, below the fish or above the fish? Where would you aim if you were trying to hit the fish with a laser beam?




4)        The refractive index of water is 1.33. What is the speed of light in water?




5)        The refractive index of diamond is 2.42. What is the speed of light in diamond?




6)        You’re looking into the ocean through the bottom of a glass-bottomed boat. The light passes from the water into the glass, through the glass, then into the air. Light is fastest in the air and slowest in the glass. Draw a diagram showing all three layers and the refractions made by the light.










7)        A ray of light shines on water, making a 35° angle with the normal to the surface. What is the angle of reflection? (There’s always a reflection whenever there’s a refraction.) What is the angle of refraction? The index of refraction for air is 1.00 and the index for water is 1.33.




8)        Light passes from the air into a beaker of ethyl alcohol (n = 1.36). The angle of incidence is 60°. What is the angle of refraction?




9)        If light passing into diamond (n = 2.42) has an angle of refraction of 15° what is the angle of incidence?




10)      The critical angle is the angle of incidence that gives an angle of refraction equal to 90°. What is the critical angle for a light ray passing from water into air?