Chapter 4

Hydrogen has absorption lines at 656 nm and 486 nm. Where are the emission lines from hydrogen in this part of the electromagnetic spectrum?

656 nm and 486 nm

For which of these scenarios is the wave model of light more convenient to use?

All of these choices are correct.

What are some of the things astronomers can learn about astronomical objects from their spectra?

All of these choices are correct.

What is the difference between emission and absorption in an atom?

In emission, the electron goes from a higher to a lower orbit.

Adam's toy gun emits blue light, Sue's emits red light, Bonnie's emits infrared light, and James' emits ultraviolet light. Which gun produces the most energetic light?

James

____ are found in the nucleus of atoms.

Protons

In the Orion constellation are stars Rigel, a blue supergiant, and Betelgeuse, a red supergiant. Which star has a greater surface temperature?

Rigel

Why is the absorption spectrum of atomic hydrogen different from that of helium?

The energy differences between orbitals in hydrogen are different from those in helium.

A star's emission line of 656 nm appears shifted to 649 nm in the spectrum. What can you conclude from this shift?

The star is approaching you with the speed of 3,200 km/s.

The maximum temperature on the Kelvin scale is called ______________.

There is no maximum temperature on the Kelvin scale.

Of the following objects, which will emit mostly infrared light?

a cup of hot coffee

In the wave model, light is ______________.

a mix of electric and magnetic energy

Compared to the entire electromagnetic spectrum, visible light is ____.

a small fraction of the possible wavelengths of light

Which one of the following is an example of a blackbody that you see in everyday life?

a stove burner

Zero Kelvin is also known as ____.

absolute zero

A(n) ___________ spectrum has dark lines on a continuous background.

absorption

What type of spectrum is observed when the light from a hot, dense body is seen through a cooler, tenuous gas?

absorption-line

Conservation of energy requires that if an atom absorbs a photon

an electron rises to a new orbital with an energy equal to that of the previous orbital plus the energy of the photon

Spectral lines shifted toward higher frequencies are called _____.

blue shifted

A candle emits what kind of spectrum?

continuous

An incandescent bulb emits what kind of spectrum?

continuous

What type of spectrum is emitted by a heated solid object (such as the filament of an incandescent bulb)?

continuous

As the wavelength of light increases, its energy ____.

decreases

A(n) ___________ spectrum has bright lines on dark background.

emission

If an electron moves from a higher energy orbital to a lower energy one, the atom will __________.

emit a photon

An X-ray telescope placed on the surface of the Earth can detect X-rays that are emitted from a distant astrophysical source.

false

In space, X-rays travel faster than radio waves.

false

The Doppler shift applies only to the line spectrum. It does not apply to the continuous (blackbody) spectrum.

false

The lower the frequency of the electromagnetic wave, the shorter its wavelength.

false

You are heating a jar full of hydrogen and observing its spectrum. If you add more hydrogen to the jar, the position of spectral lines will change.

false

The electromagnetic waves with the highest energy are ____.

gamma rays

The energy of an ultraviolet photon is ____ a photon in the visible part of the spectrum.

higher than

As the frequency of light increases, its energy ____.

increases

The energy of a radio photon is ____ a photon in the visible part of the spectrum

lower than

A photon of blue light has ______________ a photon of red light.

more energy than

Is light a wave or a particle?

neither a wave nor a particle

Uncharged particles in an atom are called ____.

neutrons

A ____ is a particle of light.

photon

Positively-charged particles in an atom are called ____.

protons

Which kind of electromagnetic radiation has a wavelength that is about the size of a person?

radio

List these electromagnetic radiations from lowest to highest energy.

radio waves, infrared, visible light, ultraviolet, X-rays, gamma rays

Which of the following colors travels most quickly through glass or plastic?

red

The spectral lines of a star will appear ____________________ if the star is moving away from the Earth.

red shifted (i.e., shifted toward the longer wavelengths)

As a solid is heated (from a low to a high temperature) the radiated light will move through what sequence of colors?

red, yellow, blue

In materials like glass or water the speed of light is _________.

reduced

Determining the composition of an astronomical body using its emitted or reflected light is called ____.

spectroscopy

Star A is blue, Star B is yellow, and Star C is red. Which one of these is the hottest star?

star A

If an atom emits a photon, that photon must have a wavelength __________.

that corresponds to the energy difference between two orbitals

A significant source of gamma rays is __________________.

the collision of two black holes

The visible spectrum is ___________________.

the range of wavelengths of light that human eyes can detect

A continuous blackbody spectrum provides information about the surface temperature of the object.

true

A temperature of 0 Kelvin means there is essentially no motion at the atomic level.

true

An atom with 6 protons and 6 neutrons is a carbon atom, and an atom with 6 protons and 7 neutrons is also a carbon atom.

true

The Doppler shift is the same if the emitting object is moving towards you at some speed, or you (the observer) are moving towards it at that speed and it is still.

true

The chemical composition of a gas can be determined by analysis of the spectral lines of the gas.

true

When an atom emits light, an electron in it moves from a higher to a lower energy level.

true

A night vision camera

uses a detector sensitive to infrared light, so you can see objects that are warmer than their surroundings.

Which of the following colors has the shortest wavelength?

violet

The mixing of light of all visible colors results in ____ light.

white

Visible light coming from the Sun is a combination of all colors called ____ light.

white