Question 1

If an electron vibrates up and down 1000 times each second,it generates an electromagnetic wave having a
A)period of 1000 s.
B)speed of 1000 m/s.
C)wavelength of 1000 m.
D)frequency of 1000 Hz.
E)wavelength of 1000 km.

Accepted Answer

The frequency of the electromagnetic wave generated by the vibrating electron is equal to the frequency of the vibration of the electron, which is 1000 times per second or 1000 Hz.

Question 2

If an electric charge is shaken up and down
A)sound is emitted.
B)light is emitted.
C)electron excitation occurs.
D)a magnetic field is created.
E)its mass decreases.

Accepted Answer

D

Question 3

Infrared waves are often called heat waves because they
A)emanate from relatively hot sources.
B)consist of frequencies lower than those of visible light.
C)induce resonance in molecules and increase internal energy in a substance.
D)are absorbed rather than reflected by the skin.
E)are the predominant waves emitted by the sun.

Accepted Answer

Infrared waves are called heat waves because they induce resonance in molecules, increasing their internal energy, which is perceived as heat.

Question 4

Compared to ultraviolet waves,the wavelength of infrared waves is
A)shorter.
B)longer.
C)the same.

Accepted Answer

Infrared waves have longer wavelengths than ultraviolet waves. The wavelength range of infrared waves is between 700 nanometers to 1 millimeter, while the range of ultraviolet waves is between 10 nanometers to 400 nanometers. Therefore, the correct choice is B.

Question 5

The speed of light in the void between molecules in glass is
A)more than its speed in a vacuum.
B)the same as its speed in a vacuum.
C)less than its speed in a vacuum.

Accepted Answer

The speed of light is constant in a vacuum and doesn't change as it enters a transparent medium such as glass. However, when light enters a medium, it interacts with the atoms and molecules in the material, which can slow it down. In the case of glass, the speed of light is slightly slower than its speed in a vacuum, but not significantly so. Therefore, the correct answer is B, the speed of light in the void between molecules in glass is the same as its speed in a vacuum.

Question 6

Compared to its average speed in air,the average speed of a beam of light in glass is
A)more.
B)less.
C)the same.

Accepted Answer

The average speed of light in air is around 299,792 km/s, while the average speed of light in glass is around 200,000 km/s. This means that the average speed of light in glass is less than its speed in air.

Question 7

The natural frequency of the atoms in glass is in the
A)infrared part of the spectrum.
B)visible part of the spectrum.
C)ultraviolet part of the spectrum.

Accepted Answer

The natural frequency of the atoms in glass is in the ultraviolet part of the spectrum, which is why glass can block some UV light while being transparent to visible light.

Question 8

Which of these electromagnetic waves has the shortest wavelength?
A)radio waves
B)infrared waves
C)X-rays
D)ultraviolet waves
E)light waves

Accepted Answer

According to the electromagnetic spectrum, X-rays have the shortest wavelength.

Question 9

Most of the waves in the electromagnetic spectrum are
A)red light.
B)blue light.
C)green light.
D)invisible.

Accepted Answer

Most of the waves in the electromagnetic spectrum, including radio waves, microwaves, infrared radiation, ultraviolet radiation, X-rays, and gamma rays, are not visible to the human eye and are therefore considered invisible.

Question 10

The fact that light travels at 300,000 km/s is a consequence of
A)electromagnetic wave propagation.
B)electromagnetic field induction.
C)Maxwell's laws.
D)energy conservation.
E)none of these

Accepted Answer

The answer of The fact that light travels at 300,000...

Question 11

Consider light energy that is momentarily absorbed in glass and then re-emitted.Compared to the absorbed light,the frequency of the re-emitted light is
A)considerably less.
B)slightly less.
C)the same.
D)slightly more.
E)considerably more.

Accepted Answer

When light is absorbed by glass, the electrons in the glass molecules get excited and jump to higher energy levels. As they return to their original energy levels, they re-emit the absorbed light energy. Since the energy levels of the glass molecules are fixed, the frequency of the absorbed and re-emitted light is the same. Therefore, the correct answer is C) the same.

Question 12

Materials generally become warmer when light is
A)absorbed by them.
B)reflected by them.
C)transmitted by them.
D)all of these
E)none of these

Accepted Answer

When light is absorbed by a material, the energy of the light is converted into thermal energy, which causes the material to become warmer. Reflected or transmitted light does not transfer energy to the material, so it does not cause the material to heat up.

Question 13

The source of all electromagnetic waves is
A)changes in atomic energy levels.
B)vibrating atoms.
C)accelerating electric charges.
D)crystalline fluctuations.
E)none of these

Accepted Answer

Electromagnetic waves are produced by accelerating electric charges, which can be in the form of electrons moving in a wire, or electrons in an antenna oscillating back and forth. This acceleration causes oscillations in the electromagnetic field, creating waves that propagate through space.

Question 14

Sunburns are produced by
A)ultraviolet light.
B)visible light.
C)infrared light.
D)all of these
E)none of these

Accepted Answer

Sunburns are produced by UV radiation which is a type of electromagnetic radiation with shorter wavelengths than visible light and longer wavelengths than X-rays. Infrared and visible light are not powerful enough to cause sunburn.

Question 15

When ultraviolet light is incident upon glass,atoms in the glass
A)are forced into vibration.
B)resonate.
C)pass the light energy along practically undiminished.
D)freely absorb and re-emit most of the ultraviolet light.

Accepted Answer

The answer of When ultraviolet light is incident upon glass,atoms...

Question 16

The main difference between a radio wave and a light wave is its
A)speed.
B)wavelength.
C)frequency.
D)all of these
E)two of these

Accepted Answer

Radio waves and light waves differ primarily in their wavelength and frequency, not speed, as they both travel at the speed of light in a vacuum.

Question 17

When visible light is incident upon clear glass,atoms in the glass
A)are forced into vibration.
B)resonate.
C)convert the light energy into internal energy.

Accepted Answer

When visible light is incident upon clear glass, atoms in the glass are forced into vibration. This is due to the interaction between the electromagnetic field of the incoming light and the charged particles in the glass. This vibration of atoms leads to absorption and transmission of the light by the glass.

Question 18

Electromagnetic waves consist of
A)compressions and rarefactions of electromagnetic pulses.
B)oscillating electric and magnetic fields.
C)particles of light energy.
D)high-frequency gravitational waves.

Accepted Answer

Electromagnetic waves consist of oscillating electric and magnetic fields that propagate through space. They do not involve compressions and rarefactions of electromagnetic pulses or particles of light energy. Gravitational waves are a different type of wave that are not electromagnetic in nature.

Question 19

Which of the following is fundamentally different from the others?
A)sound waves
B)X-rays
C)gamma rays
D)light waves
E)radio waves

Accepted Answer

Sound waves are mechanical waves that require a medium to travel through, unlike X-rays, gamma rays, light waves, and radio waves, which are all electromagnetic waves and can travel through a vacuum.

Question 20

Compared to radio waves,the velocity of visible light waves in a vacuum is
A)less.
B)more.
C)the same.

Accepted Answer

The velocity of visible light waves in a vacuum is the same as the velocity of radio waves in a vacuum, which is approximately 3 x 10^8 meters per second. This is known as the speed of light or c.

Quiz 26: Properties of Light

If an electron vibrates up and down 1000 times each second,it generates an electromagnetic wave having a

If an electric charge is shaken up and down

Infrared waves are often called heat waves because they

Compared to ultraviolet waves,the wavelength of infrared waves is

The speed of light in the void between molecules in glass is

Compared to its average speed in air,the average speed of a beam of light in glass is

The natural frequency of the atoms in glass is in the

Which of these electromagnetic waves has the shortest wavelength?

Most of the waves in the electromagnetic spectrum are

The fact that light travels at 300,000 km/s is a consequence of

Consider light energy that is momentarily absorbed in glass and then re-emitted.Compared to the absorbed light,the frequency of the re-emitted light is

Materials generally become warmer when light is

The source of all electromagnetic waves is

Sunburns are produced by

When ultraviolet light is incident upon glass,atoms in the glass

The main difference between a radio wave and a light wave is its

When visible light is incident upon clear glass,atoms in the glass

Electromagnetic waves consist of

Which of the following is fundamentally different from the others?

Compared to radio waves,the velocity of visible light waves in a vacuum is