What is the speed of light in water? In glycerine?

25. A fisherman in a boat is looking straight down through the water at a light bulb on the bottom of the lake. The lake is 10 ft deep at this point and filled with water (n=1.33). If the fisherman begins rowing directly away from the light bulb, how far can he travel across the water before he can no longer see the light bulb at all?

A spotlight is on the ground 20 ft away from a wall and a 6 ft tall person is walking towards the wall at a rate of 2.5 ft/sec. How fast is the height of the shadow changing when the person is 8 feet from the wall? (A) -2.0833 B) -0.5433 C) -0.4533 D) -2.0444

A ray of light strikes a flat glass block at an incidence angle of 8₁ = 39.8°. The glass is 2.00 cm thick and has an index of refraction that equals n = 1.65. 2.00 cm (a) What is the angle of refraction, 82, that describes the light ray after it enters the glass from above? (Enter your answer in degrees to at least 2 decimal places.) (b) with what angle of incidence, 83, does the ray approach the interface at the bottom of the glass? (Enter your answer in degrees to at least 2 decimal places.) (c) with what angle of refraction, 084, does the ray emerge from the bottom of the glass? (Enter your answer in degrees to at least 1 decimal place.)