Chapter 3

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

'False

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

1/81 as much

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

16.

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

396 nm

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

6000 K

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

81.

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

False

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

False

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

False

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

False

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

False

Wave energy can only be transmitted through a material medium.

False

Wein's law relates the peak wavelength of the blackbody to its size. The larger the black body, the shorter its peak wavelength.

False

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

False

What is true of a blackbody?

Its energy peaks at the wavelength determined by its temperature.

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

Kelvin

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

Nothing can be inferred from the information given.

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

Star A and star B have the same color, but star A is brighter.

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

Star A is bluer and brighter than star B.

Star A has a temperature 1/2 that of star B, but star A is 5 times bigger than star B. Which statement below is correct?

Star A is redder and brighter than star B.

Star A has a temperature 1/2 that of star B, but star A is 3 times bigger than star B. Which statement below is correct?

Star A is redder and dimmer than star B.

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?

Star A is redder and dimmer than star B.

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

Star B must be bigger.

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

They are in phase but perpendicular to each other in space.

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

True

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

True

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

True

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

True

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

X-ray

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

X-rays don't reach the surface of Earth.

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

bluer than it is.

Electromagnetic radiation:

can behave both as a wave and as a particle.

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

decrease by a factor of 2.

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

frequencies.

A wave's velocity is the product of the:

frequency times the wavelength of the wave.

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

infrared

If a wave's frequency doubles, its wavelength:

is halved.

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

its peak on the Planck curve will move into the infrared.

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

no shift.

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

radial motion.

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

radio

There are no radio telescopes in space because:

radio waves penetrate Earth's atmosphere so there is no need to put one in space.

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

radio waves.

Electromagnetic radiation with a wavelength of 700 nm would be:

red light.

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

temperature.

Stefan's Law says:

that if the Sun's temperature were doubled, it would give off 16X more energy.

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

the X-ray

The total energy radiated by a blackbody depends on:

the fourth power of its temperature.

The number of waves passing the observer per second is:

the frequency in Hertz.

A dim, young star like Herbig-Haro 68 emits most of its light in which part of the electromagnetic spectrum?

the infrared

What does the phenomenon of interference demonstrate?

the particle nature of the photon

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

the radio

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

the ultraviolet

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

the visible

What does the phenomenon of diffraction demonstrate?

the wave nature of light

Both sound waves and electromagnetic radiation:

transfer energy.

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

ultraviolet

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

velocity

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

violet.

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

visible

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

visible and radio waves.

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

yellow-green at about 550 nm