# Worksheet: Refraction

Q1:

Find the speed of light in air. Use a value of 1.000293 for the refractive index of air.

• A m/s
• B m/s
• C m/s
• D m/s
• E m/s

Q2:

The refractive index of water is 1.333. What is the speed of light in water?

• A m/s
• B m/s
• C m/s
• D m/s
• E m/s

Q3:

The refractive index of glycerine is 1.473. What is the speed of light in glycerine?

• A m/s
• B m/s
• C m/s
• D m/s
• E m/s

Q4:

The refractive index of crown glass is 1.52. What is the speed of light in crown glass?

• A m/s
• B m/s
• C m/s
• D m/s
• E m/s

Q5:

Determine how far light travels underwater during a time interval of 1.50 µs. Use a value of 1.333 for the refractive index of water.

Q6:

Components of some computers communicate with each other through optical fibers having a refractive index of 1.55. What time in nanoseconds is required for a signal to travel 0.200 m through such a fiber?

Q7:

A light beam in air is incident on the surface of a pond with a refractive index of 1.333, making an angle of 20° with respect to the surface of the pond.

What is the angle of reflection?

• A
• B
• C
• D
• E

What is the angle of refraction?

• A
• B
• C
• D
• E

Q8:

The path of a light beam in air goes from an angle of incidence of to an angle of refraction of when it enters a rectangular block of plastic. What is the index of refraction of the plastic?

Q9:

A pencil flashlight submerged in water sends a light beam toward the surface at an angle of incidence of from the water-air boundary. Find the angle of refraction in air. Use a value of 1.33 for the refractive index of water.

• A
• B
• C
• D
• E

Q10:

A ray of light is shown going from air (refractive index of 1.00) through crown glass (refractive index of 1.52) into water (refractive index of 1.33), such as going into a fish tank. Calculate the amount the ray is displaced by the glass , given that the incident angle is and the glass is 1.00 cm thick.

Q11:

In which substance from this table is the speed of light m/s?

Medium
Gases at , 1 atm
Air 1.000293
Carbon dioxide 1.00045
Hydrogen 1.000139
Oxygen 1.000271
Liquids at
Benzene 1.501
Carbon disulfide 1.628
Carbon tetrachloride 1.461
Ethanol 1.361
Glycerine 1.473
Water, fresh 1.333
Solids at
Diamond 2.419
Fluorite 1.434
Glass, crown 1.52
Glass, flint 1.66
Ice (at ) 1.309
Polystyrene 1.49
Plexiglas 1.51
Quartz, crystalline 1.544
Quartz, fused 1.458
Sodium chloride 1.544
Zircon 1.923
• A Fluorite
• B Ethanol
• C Plexiglas
• D Ice at ()
• E Benzene

Q12:

A laser emits red light that has a wavelength of 633 nm. The light is transmitted into glass in which it propagates at m/s, while retaining the same frequency that it had while propagating in air.

What is the frequency of the light?

• A Hz
• B Hz
• C Hz
• D Hz
• E Hz

What is the wavelength of the light in the glass?

Q13:

Calculate the index of refraction for a medium in which the speed of light is m/s.

Q14:

When the Moon was originally formed, it was much closer to Earth than it is today. When the Moon was only m from Earth, how much time did light from the Moon take to reach Earth?

Q15:

What is the time taken for a light ray to travel 4.0 km in a vacuum?

• A s
• B s
• C s
• D s
• E s

Q16:

Lunar astronauts have placed a corner reflector on the Moon’s surface. A laser beam from Earth is periodically fired at the reflector and reflected back by it to the beam’s source. The distance to the Moon is calculated from the time between emitting the beam and detecting its reflection. The distance from Earth to the Moon is also calculated by parallax measurement and found to be m. The distance found using the reflected laser measurement of the distance is found to be greater than the distance found by parallax as the light is slowed slightly when it moves through Earth’s atmosphere. Find the percentage increase in the round-trip time taken by the laser beam due to the effect of Earth’s atmosphere. Use a value of 30.0 km for the thickness of Earth’s atmosphere and a value of 1.00394 for the average refractive index of the atmosphere.

• A
• B
• C
• D
• E

Q17:

A light beam in air is incident on a plane surface of glass at an angle of to the surface. Find the angle to the surface at which the refracted beam propagates in the glass. Use a value of 1.52 for the refractive index of the glass.

Q18:

A light ray traveling through water is incident on a plane glass surface at an angle from a line normal to the surface. The light ray propagates through the glass at an angle of from the normal of the surface. Find . Use a value of 1.33 for the refractive index of water and use a value of 1.52 for the refractive index of glass.

Q19:

A secret agent is pursued through some woodland by an armed guard carrying a gun with a laser targeting sight. The agent attempts to lose the pursuing guard by diving into a lake. While underwater, the agent sees the laser beam from the guard’s gunsight in the water near him and notes that the beam is at an angle of to the vertical. Find the angle above the horizontal at which the laser beam must be incident on the surface of the water. Use a value of 1.33 for the refractive index of water. Assume that the surface of the lake is perfectly horizontal.

Q20:

An object made of an unknown substance is immersed in water. A ray of light is directed at the object at an angle of from the object’s surface. The light ray propagates within the substance at an angle of from the normal to the object’s surface. Find the refractive index of the substance. Use a value of 1.33 for the refractive index of water.

Q21:

A light ray propagating in water strikes the surface of a gemstone at an angle of from the normal to the surface. The light ray propagates within the gemstone at an angle of from the normal to the surface. Find the speed of light in the gemstone. Use a value of 1.33 for the refractive index of water.

• A m/s
• B m/s
• C m/s
• D m/s
• E m/s

Q22:

Find the speed of light in benzine. Use a value of 1.501 for the index of refraction of benzine.

• A m/s
• B m/s
• C m/s
• D m/s
• E m/s

Q23:

Find the speed of light in ethanol. Use a value of 1.361 for the index of refraction of ethanol.

• A m/s
• B m/s
• C m/s
• D m/s
• E m/s

Q24:

What is the time required for electromagnetic radiation to travel a distance of 1 nm in a vacuum?

• A s
• B s
• C s
• D s
• E s

Q25:

A light ray propagating in air is incident on an air-glass interface, and after propagating through glass, it is incident on a glass-water interface, as shown. Assuming that the angle from the normal of the air-glass interface at which the light ray strikes the glass surface is , find the angle from the normal to the glass-water interface at which the light ray propagates in water. Use a value of 1.33 for the refractive index of water and a value of 1.52 for the refractive index of glass.