Deck 8: Electromagnetism and Em Waves

Question 1

A transformer only works with AC.

Answer 1

True

Question 2

An electric motor can be manually turned and made to act as a generator.

Answer 2

True

Question 3

There are positive and negative magnetic charges, analogous to positive and negative electric charges.

Answer 3

False

Question 4

The deviation from the way a compass needle points from the true north direction is the magnetic declination.

Question 5

Moving electric charges make magnetic fields.

Question 6

Blackbody radiation is emitted from a small hole in a furnace.

Question 7

The direction of a magnetic field at a point can be determined by a compass.

Question 8

The increase in the amount of carbon dioxide in the atmosphere is contributing to the greenhouse effect.

Question 9

X rays are used in radar.

Question 10

The main form of radiation that our bodies emit is ultraviolet.

Question 11

A speaker can be used as a crude microphone.

Question 12

One can reverse the north and south poles of an electromagnet by reversing the direction of current flow through it.

Question 13

The frequency of visible light determines its color.

Question 14

Bones show up in x ray images because they absorb x rays more efficiently than muscle and other tissues do.

Question 15

Three devices that use electromagnetic induction in their operation are generators, transformers, and dynamic microphones.

Question 16

The greenhouse effect occurs because carbon dioxide in the atmosphere absorbs ultraviolet radiation.

Question 17

The ozone layer absorbs infrared radiation from sunlight.

Question 18

The ionosphere reflects high frequency radio waves.

Question 19

The shape of the magnetic field around a bar magnet is very close to the shape of the electric field around a single positive charge.

Question 20

A stationary electric charge produces a magnetic field around it.

Question 21

For a body emitting blackbody radiation, the total power emitted is proportional to the 4th power of the body's absolute temperature: ( T in kelvins)
and the wavelength of the emitted EM radiation that has the highest intensity is inversely proportional to the body's absolute temperature according to: ( in meters, T in kelvins)
Assume an object is emitting blackbody radiation.
A body in a room at 300 K is heated to 3,000 K. The wavelength of the most intense EM radiation emitted by the body at 3,000 K is 10 times the wavelength of the most intense EM radiation at 300 K.

Question 22

For a body emitting blackbody radiation, the total power emitted is proportional to the 4th power of the body's absolute temperature: ( T in kelvins)
and the wavelength of the emitted EM radiation that has the highest intensity is inversely proportional to the body's absolute temperature according to: ( in meters, T in kelvins)
Assume an object is emitting blackbody radiation.
A body in a room at 300 K is heated to 3,000 K. The amount of energy radiated each second by the body increases 10,000 times.

Question 23

The cosmic background radiation corresponds to a blackbody at a temperature of 2.726 kelvins.

Question 24

AM radio stations have greater range than FM stations because they have more powerful transmitters.

Question 25

For a body emitting blackbody radiation, the total power emitted is proportional to the 4th power of the body's absolute temperature: ( T in kelvins)
and the wavelength of the emitted EM radiation that has the highest intensity is inversely proportional to the body's absolute temperature according to: ( in meters, T in kelvins)
Assume an object is emitting blackbody radiation.
If the Kelvin temperature of a body is doubled, the wavelength of the most intense light is double the wavelength originally of the most intense light.

Question 26

A coil of wire is connected to a galvanometer. When the coil is rotated in a magnetic field, the galvanometer records a current because the free electrons in the moving wire experience a force from the magnetic field that pushes them through the wire.

Question 27

Infrared radiation causes your skin to tan.

Question 28

For a body emitting blackbody radiation, the total power emitted is proportional to the 4th power of the body's absolute temperature: ( T in kelvins)
and the wavelength of the emitted EM radiation that has the highest intensity is inversely proportional to the body's absolute temperature according to: ( in meters, T in kelvins)
Assume an object is emitting blackbody radiation.
The peak of a body's blackbody radiation curve shifts upward as the temperature of the body increases.

Question 29

A coil of wire is connected to a galvanometer. When a bar magnet is moved in and out of the coil, the galvanometer records a current because of electromagnetic induction.

Question 30

Gamma radiation is the highest frequency of EM waves.

Question 31

For a body emitting blackbody radiation, the total power emitted is proportional to the 4th power of the body's absolute temperature: ( T in kelvins)
and the wavelength of the emitted EM radiation that has the highest intensity is inversely proportional to the body's absolute temperature according to: ( in meters, T in kelvins)
Assume an object is emitting blackbody radiation.
As the temperature of an object increases, the wavelength of the brightest light emitted increases.

Question 32

For a body emitting blackbody radiation, the total power emitted is proportional to the 4th power of the body's absolute temperature: ( T in kelvins)
and the wavelength of the emitted EM radiation that has the highest intensity is inversely proportional to the body's absolute temperature according to: ( in meters, T in kelvins)
Assume an object is emitting blackbody radiation.
If the Kelvin temperature of an object is doubled, the amount of radiant energy emitted each second is twice the original amount.

Question 33

The wavelength of a radio wave from an FM station broadcasting at 93.9 megahertz on your radio dial is 0.313 meters.

Question 34

Blue light has a longer wavelength than red light.

Question 35

For a body emitting blackbody radiation, the total power emitted is proportional to the 4th power of the body's absolute temperature: ( T in kelvins)
and the wavelength of the emitted EM radiation that has the highest intensity is inversely proportional to the body's absolute temperature according to: ( in meters, T in kelvins)
Assume an object is emitting blackbody radiation.
As the temperature of a body increases the color of the body shifts from blue to red.

Question 36

Gamma rays are emitted when high speed electrons decelerate as they are smashed into a metal target.

Question 37

For a body emitting blackbody radiation, the total power emitted is proportional to the 4th power of the body's absolute temperature: ( T in kelvins)
and the wavelength of the emitted EM radiation that has the highest intensity is inversely proportional to the body's absolute temperature according to: ( in meters, T in kelvins)
Assume an object is emitting blackbody radiation.
The peak of a body's blackbody radiation curve shifts toward longer wavelength as the temperature of the body increases.

Question 38

A changing magnetic field produces an electric field.

Question 39

The wavelength of a radio wave from an AM station broadcasting at 1,000 kilohertz on your radio dial is 300 meters.

Question 40

EM waves travel at a speed that varies with their wavelength.

Question 41

The greenhouse effect occurs because

A) low frequency EM waves are reflected from the atmosphere.
B) high frequency EM waves are reflected from the atmosphere.
C) the ozone layer absorbs ultraviolet light.
D) carbon dioxide in the atmosphere absorbs infrared radiation.
E) none of the above

Question 42

The ionosphere

A) reflects all EM waves.
B) reflects high frequency radio waves.
C) reflects low frequency radio waves.
D) is responsible for the greenhouse effect.
E) absorbs ultraviolet light in sunlight.

Question 43

The radiation emitted from a small hole in a furnace is

A) ultraviolet.
B) infrared.
C) x-ray.
D) microwave.
E) blackbody.

Question 44

The ionosphere can be used to conduct radio communications over long distances.

Question 45

Of the following gases, which is the most important contributor to the Earth's greenhouse effect?

A) water vapor
B) ozone
C) CFCs
D) methane

Question 46

Higher frequency radio waves are reflected by the ionosphere.

Question 47

The deviation from the way a compass needle points from the true north direction is the

A) greenhouse effect.
B) magnetic inclination.
C) magnetic declination.
D) magnetic resonance effect.
E) none of the above

Question 48

Thermograms use ultraviolet radiation to sense heat.

Question 49

The ozone layer

A) reflects all EM waves.
B) reflects high frequency radio waves.
C) reflects low frequency radio waves.
D) is responsible for the greenhouse effect.
E) absorbs ultraviolet light in sunlight.

Question 50

A superconductor expels any magnetic field from its interior. This is called

A) electromagnetic induction.
B) Maxwell's effect.
C) magnetic declination.
D) the Meissner effect.
E) none of the above.

Question 51

The magnetic compass in an aircraft points to the geographic North Pole.

Question 52

A magnetic field exerts a force on an electric charge if the charge is

A) positive.
B) negative.
C) moving.
D) stationary.
E) any of the above.

Question 53

The direction of a magnetic field at a point can be determined by

A) a generator.
B) a compass.
C) a transformer.
D) electromagnetic induction.
E) none of the above.

Question 54

N rays do not exist.

Question 55

A magnetic field is created by an electric charge if the charge is

A) positive.
B) negative.
C) moving.
D) stationary.
E) any of the above.

Question 56

The main form of radiation that our bodies emit is

A) ultraviolet.
B) infrared.
C) x-ray.
D) microwave.
E) blackbody.

Question 57

An iron nail is brought near a magnet. Which of these is not true?

A) The nail has a north pole and a south pole.
B) The nail becomes a north pole or a south pole.
C) The magnet exerts an attractive force on the nail.
D) The nail exerts an attractive force on the magnet.
E) The nail is ferromagnetic.

Question 58

The greenhouse effect is occurring because

A) the ozone layer is being depleted.
B) the amount of carbon dioxide in the atmosphere is increasing.
C) the ionosphere reflects low frequency radiation.
D) more ultraviolet radiation is penetrating the atmosphere.
E) none of the above.

Question 59

The type of EM waves used in radar is

A) ultraviolet.
B) infrared.
C) x-ray.
D) microwave.
E) blackbody.

Question 60

Electromagnetic induction is used in the operation of

A) generators.
B) transformers.
C) dynamic microphones.
D) regenerative braking.
E) all of the above.

Question 61

The EM wave that has the smallest wavelength in this list is

A) ultraviolet.
B) infrared.
C) x-rays.
D) microwave.
E) gamma rays.

Question 62

What's the Big Bang?

A) the creation of the universe
B) microwave radiation from all directions in the sky
C) the Hubble relation
D) a punk rock band

Question 63

The highest frequency visible light is

A) violet.
B) red.
C) blue.
D) green.
E) yellow.

Question 64

For a body emitting blackbody radiation, the total power emitted is proportional to the 4th power of the body's absolute temperature: ( T in kelvins)
And the wavelength of the emitted EM radiation that has the highest intensity is inversely proportional to the body's absolute temperature according to: ( in meters, T in kelvins)
Assume an object is emitting blackbody radiation.
As the temperature of an object increases, the wavelength of the brightest light emitted

A) increases.
B) decreases.
C) doesn't change.
D) depends on the composition of the body.
E) depends on the size of the body.

Question 65

Global warming

A) has not yet been observed.
B) has been caused by increasing levels of carbon dioxide in the atmosphere.
C) has led to a depletion of the ozone layer in the atmosphere.
D) has no serious consequences.

Question 66

The type of EM radiation emitted when high speed electrons decelerate as they are smashed into a metal target is

A) ultraviolet.
B) infrared.
C) x-ray.
D) microwave.
E) gamma ray.

Question 67

The EM wave that has the lowest frequency in this list is

A) ultraviolet.
B) infrared.
C) x-rays.
D) microwave.
E) gamma rays.

Question 68

The type of EM wave having the highest frequency is

A) ultraviolet.
B) infrared.
C) x-rays.
D) microwave.
E) gamma rays.

Question 69

The wavelength from an FM station broadcasting at 93.9 megahertz on your radio is

A) 31.3 m.
B) 3.13 m.
C) 0.313 m.
D) 0.0313 m.
E) none of the above.

Question 70

For a body emitting blackbody radiation, the total power emitted is proportional to the 4th power of the body's absolute temperature: ( T in kelvins)
And the wavelength of the emitted EM radiation that has the highest intensity is inversely proportional to the body's absolute temperature according to: ( in meters, T in kelvins)
Assume an object is emitting blackbody radiation.
If the Kelvin temperature of an object is doubled, the amount of radiant energy emitted each second is ____________ the original amount.

A) 1/16th
B) half
C) the same as
D) 2 times
E) 16 times

Question 71

The type of EM radiation that causes your skin to tan is

A) ultraviolet.
B) infrared.
C) x-rays.
D) microwave.
E) gamma rays.

Question 72

How can microwave ovens heat food more quickly than conventional ovens?

A) Microwaves give energy directly to the molecules in the food.
B) Conventional ovens must conduct heat from the surface to the interior of the food.
C) Microwaves heat the inside as well as the surface of the food.
D) all of the above

Question 73

The type of EM radiation that has wavelength just a bit longer than that of visible light is

A) ultraviolet.
B) infrared.
C) x-ray.
D) microwave.
E) gamma ray.

Question 74

The lowest frequency visible light is

A) violet.
B) red.
C) blue.
D) green.
E) yellow.

Question 75

AM radio stations have greater range than FM stations because

A) AM is more efficient than FM.
B) they have more powerful transmitters.
C) their lower frequency radio waves reflect off the ionosphere.
D) none of the above

Question 76

For a body emitting blackbody radiation, the total power emitted is proportional to the 4th power of the body's absolute temperature: ( T in kelvins)
And the wavelength of the emitted EM radiation that has the highest intensity is inversely proportional to the body's absolute temperature according to: ( in meters, T in kelvins)
Assume an object is emitting blackbody radiation.
If the Kelvin temperature of a body is doubled, the wavelength of the most intense light is ____________ the wavelength originally of the most intense light.

A) 1/16th
B) half
C) the same as
D) 2 times
E) 16 times

Question 77

FM radio only operates in the frequency range 88 MHz to 108 MHz because

A) higher or lower frequencies are blocked by the ionosphere.
B) higher and lower frequencies are not radio waves.
C) the government set those limits.
D) none of the above

Question 78

Which of the following is not a common use of microwaves?

A) cooking
B) medical imaging
C) radar
D) communications

Question 79

The type of EM radiation that has wavelength just a bit shorter than that of visible light is

A) ultraviolet.
B) infrared.
C) x-ray.
D) microwave.
E) gamma ray.

Question 80

Why would a decrease in the amount of ozone in the atmosphere increase the likelihood of people getting sunburn?

A) Global temperatures would rise
B) More ultraviolet radiation would reach the ground
C) People would be exposed to more infrared radiation
D) The premise is incorrect. Ozone and sunburn are not related