4.4 Refraction

What is the best estimate for the refractive index of a medium in which light travels at a speed of 2.7×10⁸ ms⁻¹?

• 0.9

• 1.0

• 1.1

• 1.2

A ray of light is incident on a boundary between glass and air.

Which of the following is the refractive index of glass?

• $\frac{\sin\ \theta_1}{\sin\ \theta_4}$

• $$\frac{\sin {\theta }_1}{\sin {\theta }_3}$$

• $\frac{\sin\ \theta_3}{\sin\ \theta_2}$

• $\frac{\sin\ \theta_4}{\sin\ \theta_1}$

Monochromatic light travels from air into water. Which of the following describes the changes in wavelength and speed?

• Wavelength: decreases

  Speed: decreases

• Wavelength: increases

  Speed: decreases

• Wavelength: decreases

  Speed: increases

• Wavelength: increases

  Speed: increases

Light travels from air into glass as shown below.

What is the refractive index of glass?

• $\frac{\sin\ P}{\sin\ S}$

• $\frac{\sin\ Q}{\sin\ R}$

• $\frac{\sin\ Q}{\sin\ R}$

• $\frac{\sin\ Q}{\sin\ S}$

Light travels from air into glass as shown below.

The refractive index is

• $\frac{\sin\ 30\degree}{\sin\ 80\degree}$

• $\frac{\sin\ 80\degree}{\sin\ 30\degree}$

• $\frac{\sin\ 60\degree}{\sin\ 10\degree}$

• $\frac{\sin\ 10\degree}{\sin\ 60\degree}$

A ray of light travels from a vacuum into glass as shown below.

In glass, light has speed v. In a vacuum, light has speed c. Which of the following gives the refractive index of glass?

• $\frac{v}{c}$

• $\frac{c}{v}$

• $\frac{\sin\ v}{\sin\ c}$

• $\frac{\sin\ c}{\sin\ v}$

Light of wavelength 600 nm travels from air to glass at normal incidence. The refractive index of the glass is 1.5. The speed of light in air is c. Which of the following correctly identifies the speed of the waves and their wavelength in the glass?B

• A

• B

• C

• D

When a sound wave travels from a region of hot air to a region of cold air, it refracts as shown.

What changes occur in the frequency and wavelength of the sound as it passes from the hot air to the cold air?

• Frequency: unchanged

  Wavelength: increases

• Frequency: unchanged

  Wavelength: decreases

• Frequency: increases

  Wavelength: increases

• Frequency: decreases

  Wavelength: decreases