25.4 Total internal reflection  (Page 4/8)

A ring with a colorless gemstone is dropped into water. The gemstone becomes invisible when submerged. Can it be a diamond? Explain.

A high-quality diamond may be quite clear and colorless, transmitting all visible wavelengths with little absorption. Explain how it can sparkle with flashes of brilliant color when illuminated by white light.

Is it possible that total internal reflection plays a role in rainbows? Explain in terms of indices of refraction and angles, perhaps referring to [link] . Some of us have seen the formation of a double rainbow. Is it physically possible to observe a triple rainbow?

The most common type of mirage is an illusion that light from faraway objects is reflected by a pool of water that is not really there. Mirages are generally observed in deserts, when there is a hot layer of air near the ground. Given that the refractive index of air is lower for air at higher temperatures, explain how mirages can be formed.

Verify that the critical angle for light going from water to air is $\text{48.6º}$ , as discussed at the end of [link] , regarding the critical angle for light traveling in a polystyrene (a type of plastic) pipe surrounded by air.

(a) At the end of [link] , it was stated that the critical angle for light going from diamond to air is $\text{24}\text{.}\mathrm{4º}$ . Verify this. (b) What is the critical angle for light going from zircon to air?

An optical fiber uses flint glass clad with crown glass. What is the critical angle?

At what minimum angle will you get total internal reflection of light traveling in water and reflected from ice?

Suppose you are using total internal reflection to make an efficient corner reflector. If there is air outside and the incident angle is $\text{45}\text{.}\mathrm{0º}$ , what must be the minimum index of refraction of the material from which the reflector is made?

You can determine the index of refraction of a substance by determining its critical angle. (a) What is the index of refraction of a substance that has a critical angle of $\text{68}\text{.}\mathrm{4º}$ when submerged in water? What is the substance, based on [link] ? (b) What would the critical angle be for this substance in air?

A ray of light, emitted beneath the surface of an unknown liquid with air above it, undergoes total internal reflection as shown in [link] . What is the index of refraction for the liquid and its likely identification?

A light ray entering an optical fiber surrounded by air is first refracted and then reflected as shown in [link] . Show that if the fiber is made from crown glass, any incident ray will be totally internally reflected.