Question 1

The radial velocity of a star's motion in space can also broaden its spectral lines.

Accepted Answer

False

Question 2

An X-ray photon has more energy than a visible photon.

Accepted Answer

X-ray photons have a higher frequency and shorter wavelength than visible photons, which means they have more energy.

Question 3

The absorption lines for a cool thin gas are identical in color and energy to the emission lines of the same gas if hot enough to glow.

Accepted Answer

This is known as Kirchhoff's law, which states that a cool, thin gas will produce absorption lines at the same wavelengths as the corresponding emission lines produced by a hot gas.

Question 4

The red hydrogen alpha line carries more energy per photon than the blue-green hydrogen beta line does.

Accepted Answer

The energy of a photon is inversely proportional to its wavelength. The red hydrogen alpha line has a longer wavelength than the blue-green hydrogen beta line, meaning it carries less energy per photon.

Question 5

In the Bohr model,the transitions of electrons down to ground state produce the Lyman lines in the ultraviolet.

Accepted Answer

This statement is true according to the Bohr model, which explains the spectral lines of hydrogen. The Lyman series corresponds to transitions of electrons from higher energy levels down to the ground state, emitting photons in the ultraviolet region of the spectrum.

Question 6

Molecular spectra,like elemental ones,involve only the vibration of the particles.

Accepted Answer

Molecular spectra involve not only the vibration but also the rotation of the particles, thus making them more complex than elemental spectra.

Question 7

If a fire truck's siren is rising in pitch,it must be approaching us.

Accepted Answer

When the siren of a fire truck is rising in pitch, it means that the truck is getting closer to the listener, so it must be approaching.

Question 8

A cool,thin gas produces absorption lines.

Accepted Answer

This is because when light passes through a cool, thin gas, certain wavelengths of light are absorbed, resulting in dark lines in the spectrum of the light. These dark lines are called absorption lines, and they indicate the presence of specific elements in the gas that are absorbing the light.

Question 9

The Doppler effect can reveal the rotation speed of a star by the splitting of the spectral lines.

Accepted Answer

The answer of The Doppler effect can reveal the rotation...

Question 10

Spectroscopy of a star can reveal its temperature,composition,and line-of-sight motion.

Accepted Answer

Spectroscopy involves the analysis of the spectrum of light emitted or absorbed by a star, which can give information on its temperature, composition of elements, and motion (through Doppler shift).

Question 11

A low-density,hot gas produces a continuous spectrum.

Accepted Answer

A low-density, hot gas produces an emission spectrum, which consists of bright lines on a dark background, not a continuous spectrum.

Question 12

Only a hot,thin gas can produce an emission line.

Accepted Answer

An emission line is produced when atoms in a gas become excited and then release energy in the form of light. This can only happen in a hot, thin gas where there are few collisions between atoms that could prevent the excited state and subsequent emission.

Question 13

The larger the redshift,the faster the distant galaxy is rushing toward us.

Accepted Answer

The opposite is true. The larger the redshift, the faster the distant galaxy is moving away from us. This is due to the expansion of the universe.

Question 14

The spectral lines of each element are distinctive to that element,whether we are looking at emission or absorption lines.

Accepted Answer

The spectral lines of each element are unique to that element, allowing scientists to identify them through their emission or absorption spectra.

Question 15

The shorter a wave's wavelength,the greater its energy.

Accepted Answer

This statement is true. The energy of a wave is directly proportional to its frequency, which is inversely proportional to its wavelength. Therefore, as wavelength decreases, frequency and energy increase.

Question 16

A low density gas must be hot in order to produce an absorption line.

Accepted Answer

A low density gas must be cool in order to produce an absorption line. This is because the cooler gas will have atoms in their ground state, which can absorb specific wavelengths of light, creating the dark absorption lines in a spectrum. A hot gas will have more excited atoms, making it difficult for the atoms to absorb specific wavelengths, resulting in a more continuous spectrum.

Question 17

The Balmer lines of hydrogen involve electron transitions from the ground state to higher levels.

Accepted Answer

The Balmer lines involve electron transitions from higher energy levels (n ≥ 3) down to the n = 2 level, not from the ground state (n = 1).

Question 18

All wavelengths of light travel at the same speed in a vacuum,and carry the same energy per photon.

Accepted Answer

While all wavelengths of light travel at the same speed in a vacuum (the speed of light), they do not carry the same energy per photon. The energy of a photon is directly proportional to its frequency and inversely proportional to its wavelength, as described by the equation E = hf, where E is energy, h is Planck's constant, and f is frequency.

Question 19

In an atom,electrons can have only specific,allowed orbital energies.

Accepted Answer

According to the Bohr model of the atom, electrons can only occupy specific energy levels or orbitals, and cannot exist in between these levels. This is also known as quantization of energy.

Question 20

The Zeeman effect reveals the presence of strong magnetic fields by the splitting of spectral lines.

Accepted Answer

The Zeeman effect is indeed a phenomenon that reveals the presence of strong magnetic fields through the splitting of spectral lines.

Quiz 4: Spectroscopy: The Inner Workings of Atoms