9.11 Refraction  (Page 3/5)

Diffusion by reflection from a rough surface is described in this chapter. Light can also be diffused by refraction. Describe how this occurs in a specific situation, such as light interacting with crushed ice.

Why is the index of refraction always greater than or equal to 1?

Does the fact that the light flash from lightning reaches you before its sound prove that the speed of light is extremely large or simply that it is greater than the speed of sound? Discuss how you could use this effect to get an estimate of the speed of light.

Will light change direction toward or away from the perpendicular when it goes from air to water? Water to glass? Glass to air?

Explain why an object in water always appears to be at a depth shallower than it actually is? Why do people sometimes sustain neck and spinal injuries when diving into unfamiliar ponds or waters?

Explain why a person’s legs appear very short when wading in a pool. Justify your explanation with a ray diagram showing the path of rays from the feet to the eye of an observer who is out of the water.

Why is the front surface of a thermometer curved as shown?

Suppose light were incident from air onto a material that had a negative index of refraction, say –1.3; where does the refracted light ray go?

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

What is the speed of light in air? In crown glass?

Calculate the index of refraction for a medium in which the speed of light is $2\text{.}\text{012}\times {\text{10}}^8\text{m/s}$ , and identify the most likely substance based on [link] .

In what substance in [link] is the speed of light $2\text{.}\text{290}\times {\text{10}}^8\text{m/s}$ ?

There was a major collision of an asteroid with the Moon in medieval times. It was described by monks at Canterbury Cathedral in England as a red glow on and around the Moon. How long after the asteroid hit the Moon, which is $3\text{.}\text{84}\times {\text{10}}^5\text{km}$ away, would the light first arrive on Earth?

Components of some computers communicate with each other through optical fibers having an index of refraction $n=1\text{.}\text{55}$ . What time in nanoseconds is required for a signal to travel 0.200 m through such a fiber?

On the Moon’s surface, lunar astronauts placed a corner reflector, off which a laser beam is periodically reflected. The distance to the Moon is calculated from the round-trip time. What percent correction is needed to account for the delay in time due to the slowing of light in Earth’s atmosphere? Assume the distance to the Moon is precisely $3\text{.}\text{84}\times {\text{10}}^8\text{m}$ , and Earth’s atmosphere (which varies in density with altitude) is equivalent to a layer 30.0 km thick with a constant index of refraction $n=1\text{.}\text{000293}$ .