Deck 3: Radiation: Information From the Cosmos

Question 1

Radio waves travel at the speed of sound; X-rays travel at the speed of light.

Answer 1

False

Question 2

If a new wave arrives on shore every half second, then its frequency is 2 Hz.

Answer 2

True

Question 3

Radio waves, visible light, and X-rays are all a type of electromagnetic radiation.

Answer 3

True

Question 4

Wien's law relates the peak wavelength of the blackbody to its size. The larger theblackbody, the shorter its peak wavelength.

Question 5

The frequency of a water wave gives us its height.

Question 6

As they move through space, the vibrating electrical and magnetic fields of a light wave mustmove perpendicular to each other.

Question 7

Observations in the X-ray portion of the spectrum are routinely done from the surface of theEarth.

Question 8

As white light passes through a prism, the red (longer)wavelengths bend less than the blue(shorter)wavelengths, so forming the rainbow of colors.

Question 9

If a new wave arrives on shore every two seconds, then its frequency is 2 Hz.

Question 10

According to Wien's law, the higher the surface temperature of a star, the redder its color.

Question 11

Wave energy can only be transmitted through a material medium.

Question 12

Gamma rays are a type of electromagnetic radiation.

Question 13

While gravity is always attractive, electromagnetic forces are always repulsive.

Question 14

Changing the electric field will have no effect on the magnetic fields of a body.

Question 15

A blue star has a higher surface temperature than a red star.

Question 16

In a vacuum, X-rays travel faster than radio waves.

Question 17

You would perceive a change in a visible light wave's amplitude as a change in its color.

Question 18

The type of radiation that is most able to damage living cells is ultraviolet.

Question 19

X-rays travel at a greater speed than radio waves.

Question 20

The greater the disturbance of the medium, the higher the amplitude of the wave.

Question 21

An observer will measure the wavelength of waves emanating from a source that is movingaway as longer than it really is.

Question 22

Doubling the temperature of a blackbody will double the total energy it radiates.

Question 23

Consider this diagram. Which statement is true?

A)The amplitude is 4.
B)The amplitude is 6.
C)The amplitude is 8.
D)The amplitude is 12.
E)The amplitude cannot be determined from this diagram.

Question 24

Consider this diagram. Which statement is true?

A)The wavelength is 4.
B)The wavelength is 6.
C)The wavelength is 8.
D)The wavelength is 12.
E)The wavelength cannot be determined from this diagram.

Question 25

Which statement gives the relationship between the waves in the electric and magnetic fieldsin an electromagnetic wave?

A)They are in phase and parallel with each other in space.
B)They are 90 degrees out of phase but parallel in space.
C)They are in phase but perpendicular to each other in space.
D)They are 180 degrees out of phase and random in their inclinations to each other.
E)They are in phase but opposite in direction of motion.

Question 26

What does the phenomenon of interference demonstrate?

A)the wave nature of light
B)the polarization of light waves
C)the quantization of the atomic orbitals
D)the particle nature of the photon
E)the process of ionization

Question 27

The temperature scale that places zero at the point where all atomic and molecular motionceases is:

A)Fahrenheit.
B)Celsius.
C)Kelvin.
D)centigrade.
E)Ransom.

Question 28

Both sound waves and electromagnetic radiation:

A)travel at the speed of light.
B)require a medium to move through space.
C)can move through space without a medium.
D)transfer energy.
E)are transverse waves.

Question 29

In blackbody radiation, the energy is radiated uniformly in every region of the spectrum, sothe radiating body appears black in color.

Question 30

Which form of electromagnetic radiation would be blocked in the stratosphere by ozone?

A)cosmic rays
B)ultraviolet
C)visible light
D)infrared
E)microwaves

Question 31

Which type of electromagnetic radiation travels fastest in a vacuum?

A)radio
B)visible light
C)X-ray
D)gamma rays
E)They all travel at the same speed.

Question 32

The number of waves passing the observer per second is:

A)the wavelength in angstroms.
B)the amplitude in nm.
C)the frequency in Hertz.
D)the period in seconds.
E)the energy in milliwatts.

Question 33

A wave's velocity is the product of the:

A)frequency times the period of the wave.
B)period times the energy of the wave.
C)amplitude times the frequency of the wave.
D)frequency times the wavelength of the wave.
E)amplitude times the wavelength of the wave.

Question 34

What does the phenomenon of diffraction demonstrate?

A)the wave nature of light
B)the polarization of light waves
C)the quantization of atomic orbitals
D)the particle nature of the photon
E)the process of ionization

Question 35

If a wave's frequency doubles, its wavelength:

A)is halved.
B)is also doubled.
C)is unchanged, as c is constant.
D)is now 4 times longer.
E)becomes 16 times longer.

Question 36

As a star's temperature increases, the frequency of peak emission also increases.

Question 37

Electromagnetic radiation:

A)can only travel in a dense medium.
B)has only the properties of waves.
C)can behave both as a wave and as a particle.
D)is the same as a sound wave.
E)has nothing in common with radio waves.

Question 38

The speed of light in water compared to the speed of light in a vacuum is

A)slower.
B)faster.
C)the same.
D)can be faster or slower depending on the color.
E)can be faster or slower depending on the intensity.

Question 39

Which form of electromagnetic radiation is absorbed by carbon dioxide and water vapor inour atmosphere?

A)visible light
B)ultraviolet
C)infrared
D)radio
E)gamma rays

Question 40

Which of these is constant for ALL types of electromagnetic radiation in a vacuum?

A)amplitude
B)wavelength
C)frequency
D)velocity
E)photon energy

Question 41

X-ray telescopes are located in orbit around the Earth because:

A)X-ray telescopes on Earth would have to be too big.
B)X-ray telescopes are cheap and easy to launch into space.
C)there are too many X-ray telescopes on Earth, so now they are put in space.
D)X-rays don't reach the surface of Earth.
E)the X-rays that come out of the telescopes are dangerous to humans.

Question 42

According to Wien's Law, if the surface temperature is increased by a factor of 2, its peakwavelength will:

A)increase by a factor of 2.
B)decrease by a factor of 2.
C)increase by a factor of 4.
D)decrease by a factor of 4.
E)not change; Wien's law has nothing to do with peak wavelength.

Question 43

There are no radio telescopes in space because:

A)no one has built an antenna large enough to reach astronomical objects yet.
B)radio telescopes are too fragile and expensive to make to put into space.
C)there is too much radio noise in space, so a radio telescope won't work out there.
D)radio waves penetrate Earth's atmosphere so there is no need to put one in space.
E)you need an array, like the VLA, to detect ANY radio radiation, so it is just not realistic to putan entire array in space.

Question 44

The radiation our eyes are most sensitive to lies in the color:

A)red at 6563 Angstroms.
B)yellow-green at about 550 nm.
C)violet at 7,000 Angstroms.
D)blue at 4,321 nanometers.
E)black at 227 nm.

Question 45

Of all the forms of electromagnetic radiation, the one with the lowest frequency is:

A)gamma rays.
B)ultraviolet rays.
C)visible light.
D)microwaves.
E)radio waves.

Question 46

Star A has a temperature $1 / 2$ hat of star B, but star A is 5 times bigger than star B. Whichstatement below is correct?

A)Star A is redder and dimmer than star B.
B)Star A is bluer and dimmer than star B.
C)Star A is redder and brighter than star B.
D)Star A is bluer and brighter than star B.
E)Star A and star B have the same color, but star A is brighter.

Question 47

Star A and star B have the same temperature, but star B is more luminous than star A. Whatcan you infer about these two stars?

A)Star A must be bigger.
B)Star B must be bigger.
C)Star A must be redder.
D)Star B must be redder.
E)Nothing can be inferred from the information given.

Question 48

The hottest objects, with temperatures in the millions of Kelvins, give off most of theirradiation in which part of the electromagnetic spectrum?

A)visible
B)radio
C)ultraviolet
D)X-ray
E)gamma ray

Question 49

The visible color of electromagnetic radiation that has the shortest wavelength is:

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

Question 50

The Earth's ionosphere partially blocks which form of electromagnetic radiation?

A)gamma rays
B)ultraviolet
C)visible light
D)infrared
E)radio

Question 51

Star A and star B have the same temperature, but different luminosities. What can you inferabout these two stars?

A)Star A must be bigger.
B)Star B must be bigger.
C)Star A must be redder.
D)Star B must be redder.
E)Nothing can be inferred from the information given.

Question 52

Electromagnetic radiation with a wavelength of 700 nm would be:

A)X-rays.
B)red light.
C)violet light.
D)ultraviolet light.
E)microwaves.

Question 53

What is true of a blackbody?

A)It appears black to us, regardless of its temperature.
B)Its energy is not a continuum.
C)Its energy peaks at the wavelength determined by its temperature.
D)If its temperature doubled, the peak in its curve would be doubled in wavelength.
E)It has a complete absence of thermal energy.

Question 54

There are no X-ray telescopes on Earth because:

A)they are too expensive to build.
B)no one has yet invented an X-ray telescope that works.
C)we can't figure out how to direct an X-ray beam through space.
D)X-rays don't penetrate Earth's atmosphere.
E)there are no astronomical objects that emit X-rays.

Question 55

Which type of radiation can be observed well from Earth's surface?

A)gamma ray
B)X-ray
C)ultraviolet
D)visible
E)infrared

Question 56

Colors appear different to us because of their photons' different:

A)speeds.
B)amplitudes.
C)frequencies.
D)magnetic fields.
E)polarization.

Question 57

Which type of electromagnetic radiation has the shortest wavelength?

A)radio
B)infrared
C)visible light
D)ultraviolet
E)gamma ray

Question 58

The total energy radiated by a blackbody depends on:

A)the fourth power of its temperature.
B)the square of its temperature.
C)the square root of its temperature.
D)the cube root of its temperature.
E)the cube of its temperature.

Question 59

Star A has a temperature $1 / 2$ hat of star B, but star A is 3 times bigger than star B. Whichstatement below is correct?

A)Star A is redder and dimmer than star B.
B)Star A is bluer and dimmer than star B.
C)Star A is redder and brighter than star B.
D)Star A is bluer and brighter than star B.
E)Star A and star B have the same color, but star A is brighter.

Question 60

The two forms of electromagnetic radiation that penetrate the atmosphere best are:

A)X-rays and gamma rays.
B)ultraviolet and visible light.
C)visible and infrared light.
D)visible and radio waves.
E)infrared and microwaves.

Question 61

Star A and star B have the same temperature, but star A is 5 times bigger than star B. Whichstatement below is correct?

A)Star A is redder and dimmer than star B.
B)Star A is bluer and dimmer than star B.
C)Star A is redder and brighter than star B.
D)Star A is bluer and brighter than star B.
E)Star A and star B have the same color, but star A is brighter.

Question 62

Very hot, young stars, like those in Messier 2 emit most of their light in which part of theelectromagnetic spectrum?

A)the visible
B)the X-ray
C)the ultraviolet
D)the radio
E)the infrared

Question 63

Increasing the temperature of a blackbody by a factor of 2 will increase its energy by a factorof:

A) $\sqrt { 2 }$
B)4.
C)8.
D)16.
E)32.

Question 64

The light from an object moving tangentially (to your left or right)will exhibit:

A)a blueshift.
B)a redshift.
C)a shift in peak wavelength towards the red.
D)a shift in peak wavelength towards the blue.
E)no shift.

Question 65

To see the Sun's hot corona (a temperature of 1,000,000 K), which part of theelectromagnetic spectrum should one observe?

A)the visible
B)the X-ray
C)the ultraviolet
D)the radio
E)the infrared

Question 66

As the Sun evolves into a red giant in the distant future, then according to Wien's Law:

A)most of its energy must become shorter in wavelength.
B)its peak on the Planck curve will move into the infrared.
C)its total luminosity must decrease.
D)it will disappear from the universe of visible light.
E)its light will be slowed down by its increasing mass.

Question 67

If a beam of blue light with a wavelength of 400 nm is emitted by an object moving awayfrom you at $1 \%$ o the speed of light, what wavelength would you see from this light?

A)396 nm
B)399 nm
C)400 nm
D)401 nm
E)404 nm

Question 68

At which of these Kelvin temperatures would a blackbody radiate mostly at visiblewavelengths?

A)6 K
B)60 K
C)600 K
D)6000 K
E)None of these; a blackbody doesn't radiate visible light.

Question 69

Increasing the temperature of a blackbody by a factor of 3 will increase its energy by a factorof:

A)3.
B)6.
C)9.
D)12.
E)81.

Question 70

The wavelength at which a blackbody radiates most depends on its:

A)radius.
B)mass.
C)magnetic fields.
D)temperature.
E)direction of motion.

Question 71

Star A has a temperature 1/4 that of star B. Both star A and star B are the same physical size.Which statement below is correct?

A)Star A is redder and dimmer than star B.
B)Star A is bluer and dimmer than star B.
C)Star A is redder and brighter than star B.
D)Star A is bluer and brighter than star B.
E)Star A and star B have the same color, but star A is brighter.

Question 72

The Doppler Effect is a phenomenon that allows one to measure an object's:

A)temperature.
B)radius.
C)radial motion.
D)tangential motion.
E)chemical composition.

Question 73

Stars like our Sun emit most of their light in which part of the electromagnetic spectrum?

A)the visible
B)the X-ray
C)the ultraviolet
D)the radio
E)the infrared

Question 74

Star A has a temperature 3 times that of star B. Both star A and star B are the same physicalsize. Which statement about star A and star B below is correct?

A)Star A is redder and dimmer than star B.
B)Star A is bluer and dimmer than star B.
C)Star A is redder and brighter than star B.
D)Star A is bluer and brighter than star B.
E)Star A and star B have the same color, but star A is brighter.

Question 75

Per unit area (such as a square centimeter), a B star whose surface temperature is 10,000 Kwill put out how much radiation compared to an O star whose surface temperature is 30,000 K?

A)81 times as much
B)9 times as much
C) $1 / 81$ 1 s much
D) $1 / 9$ s much
E) $1 / 3$ 3 s much

Question 76

Very low temperature molecular clouds emit most of their light in which part of theelectromagnetic spectrum?

A)the visible
B)the X-ray
C)the ultraviolet
D)the radio
E)the infrared

Question 77

Stefan's Law says:

A)the hotter a star's surface, the bluer it looks to us.
B) $\mathrm { E } = \mathrm { mc } \mathrm { } ^ { 2 }$
C)the energy radiated by a blackbody is proportional to T3.
D)that if the Sun's temperature were doubled, it would give off 16X more energy.
E)that doubling the star's temperature would also double its peak wavelength.

Question 78

If a light source is approaching you at a speed very close to the speed of light, it will appear:

A)redder than it is.
B)bluer than it is.
C)brighter than it is.
D)fainter than it is.
E)lower temperature than it is.

Question 79

A dim, young star like He rbig-Haro 68 emits most of its light in which part of theelectromagnetic spectrum?

A)the visible
B)the X-ray
C)the ultraviolet
D)the radio
E)the infrared

Question 80

The distance from a wave's crest to its undisturbed state is the ________.