Question 1

The nucleus is made of ____
A) electrons only.
B) protons only.
C) neutrons only.
D) a and b, usually.
E) b and c, usually.

Accepted Answer

The nucleus of an atom is typically composed of protons and neutrons.

Question 2

Which one of the hydrogen atoms below is EMITTING light? The electron jumps from the
A) second energy level to first (most bound).
B) third energy level to fourth.
C) fourth energy level to fifth.
D) second energy level to third.
E) first energy level to second.

Accepted Answer

When an electron jumps from a higher energy level to a lower one (e.g., from the second energy level to the first), it emits light. This is because energy is released in the form of a photon during the transition.

Question 3

An atom can be ionized by ____ it.
A) removing electrons from
B) adding an electron to
C) removing a proton from
D) Either answer a or b

Accepted Answer

An atom can be ionized by either removing electrons from it (a process called ionization) or adding an electron to it (a process called electron attachment). Both options result in the formation of an ion. Removing a proton from an atom would change its atomic number and convert it into a different element, but it would not result in ionization.

Question 4

The wavelength of the hydrogen line from level 1 to level 2 in a hot star is ____________ the wavelength of the same line in a cool star. The stars have the same radial velocities away from Earth.
A) larger than.
B) the same as
C) smaller than
D) not enough information to answer

Accepted Answer

The wavelength of the hydrogen line from level 1 to level 2 is determined by the energy difference between these two levels, which is a fundamental property of hydrogen and does not depend on the temperature of the star.

Question 5

A very bright UFO is seen near the moon's orbit. An astronomer takes a spectrum of it and discovers it has a bright line spectrum on a dark background. The earth's population is near panic when the astronomer announces the UFO is
A) a metal spacecraft.
B) a giant rock about to hit Earth.
C) a glowing cloud of gas.
D) a star like the sun.

Accepted Answer

The fact that the spectrum has a bright line spectrum on a dark background suggests that it is a cloud of gas emitting light at specific wavelengths. This rules out options A, B, and D.

Question 6

The neutral hydrogen atom consists of
A) one proton and one neutron.
B) one proton.
C) one proton, one neutron, and one electron.
D) one proton and one electron.
E) an isotope and an ion.

Accepted Answer

The neutral hydrogen atom consists of one proton, which has a positive charge, and one electron, which has a negative charge. These charges cancel each other out, resulting in a neutral atom. There is no neutron in the hydrogen atom.

Question 7

If a light-emitting object is moving away from you, you observe its wavelengths to be ________ its wavelengths if it were at rest.
A) longer than
B) shorter than
C) the same as

Accepted Answer

This is known as redshift, and it occurs because as an object moves away from an observer, the wavelengths of the electromagnetic radiation it emits are stretched out, causing them to appear longer (and thus redder) than they would if the object were at rest.

Question 8

The process of removing an electron from a stable nucleus is known as ____________________.

Accepted Answer

The answer of The process of removing an electron from...

Question 9

The number of ____ in the nucleus determines what element the nucleus is.
A) protons
B) electrons
C) neutrons
D) None of these determines the element.
E) All of these determines the element.

Accepted Answer

The number of protons in the nucleus determines what element the nucleus is. This is known as the atomic number, which is unique to each element.

Question 10

The process of making an electron less tightly bound to an atom's nucleus is known as
A) excitation.
B) Doppler broadening.
C) collisional broadening.
D) a red shift.
E) quantum mechanics.

Accepted Answer

Excitation is the process of adding energy to an atom, which can result in an electron being promoted to a higher energy level and becoming less tightly bound to the nucleus.

Question 11

Two white dwarf stars are the same size, but one has a surface temperature twice as hot as the other. The hotter star will radiate
A) half as much energy per second as the cooler star.
B) the same amount of energy per second as the cooler star.
C) four times as much energy per second as the cooler star.
D) sixteen times as much energy per second as the cooler star.

Accepted Answer

The luminosity (energy radiated per second) of a star is proportional to the fourth power of its temperature (Stefan-Boltzmann law). Therefore, if one star's surface temperature is twice that of another, it will radiate $2^4 = 16$ times as much energy per second.

Question 12

Suppose the laboratory wavelength of a spectral line is 600 nm. In a star it is measured to be 599.4 nm. Is the star moving toward or away from us, relative to the line of sight? How fast is it moving? (Hint: c = 300,000 km/s)
A) toward; 300 km/s
B) away; 300 km/s
C) at rest; 0 km/s
D) sideways; 300 km/s
E) toward; 150 km/s

Accepted Answer

The star is moving toward us because the observed wavelength (599.4 nm) is shorter than the laboratory wavelength (600 nm), indicating a blueshift. The speed can be calculated using the Doppler shift formula: $v = \frac{\Delta \lambda}{\lambda} \times c = \frac{600 - 599.4}{600} \times 300,000 \, \text{km/s} = 300 \, \text{km/s}$.

Question 13

The most massive part of the atom is(are) the ____ which has(have) a ____ charge.
A) electrons; negative
B) nucleus; negative
C) electrons; positive
D) nucleus; positive

Accepted Answer

The nucleus is the most massive part of the atom and contains positively charged protons and neutral or negatively charged neutrons. The electrons are much smaller in mass and orbit around the nucleus with a negative charge. Therefore, the correct choice is D.

Question 14

If continuous spectrum light from a star passes through a cool, low-density gas on its way to your telescope and spectroscope, ____ spectrum on the continuous spectrum results.
A) a dark (absorption) line
B) a bright (emission) line
C) continuous

Accepted Answer

When continuous spectrum light from a star passes through a cool, low-density gas, the gas absorbs certain wavelengths of light, creating dark absorption lines on the continuous spectrum. Therefore, the answer is A.

Question 15

The figure shows a color image of Betelgeuse, a red giant star. Which of the surface temperatures below best matches Betelgeuse's surface temperature? Hint: Our sun at 6000 K is yellow. 
A) 64,000 K
B) 32,000 K
C) 16,000 K
D) 8000 K
E) 2000 K

Accepted Answer

Betelgeuse is a red giant star, which means it has a lower surface temperature than our sun which is yellow. Red giants can have surface temperatures as low as 2000 K, so choice E is the best match. Choices A, B, C, and D are all much hotter than Betelgeuse.

Question 16

Which of the following is not a fundamental component of the atom?
A) proton
B) neutron
C) ion
D) electron

Accepted Answer

An ion is not a fundamental component of the atom, but rather a charged atom or molecule that has gained or lost electrons. Protons, neutrons, and electrons are the fundamental components that make up an atom.

Question 17

At what wavelength would a star radiate the greatest amount of energy if the star has a surface temperature of 10,000 K? A) 10 nm B) 100 nm C) 300 nm D) 1.0*10⁴ nm E) 3.0*10¹⁰ nm

Accepted Answer

According to Wien's Law, the peak wavelength (λ_max) is inversely proportional to the temperature (T) of the star. λ_max = b/T, where b is Wien's constant (approximately 2.9*10^6 nm*K). For a temperature of 10,000 K, λ_max = 2.9*10^6 nm*K / 10,000 K = 290 nm, which is closest to 300 nm.

Question 18

Which one of the hydrogen atoms below is EMITTING light at a wavelength in the Balmer series?
A) second energy level to first (most bound)
B) third energy level to second
C) fourth energy level to third
D) second energy level to third
E) first energy level to second

Accepted Answer

The Balmer series involves transitions of electrons from higher energy levels (n > 2) to the second energy level (n=2). Choice B (third energy level to second) fits this description.

Question 19

In the diagram below, draw the transition that would emit a photon with the smallest wavelength.

Accepted Answer

The answer of In the diagram below, draw the transition...

Question 20

The ____________________ of a star can be determined from its color.

Accepted Answer

The answer of The ____________________ of a star can be...

Quiz 6: Atoms and Spectra

The nucleus is made of ____

Which one of the hydrogen atoms below is EMITTING light? The electron jumps from the

An atom can be ionized by ____ it.

The wavelength of the hydrogen line from level 1 to level 2 in a hot star is ____________ the wavelength of the same line in a cool star. The stars have the same radial velocities away from Earth.

A very bright UFO is seen near the moon's orbit. An astronomer takes a spectrum of it and discovers it has a bright line spectrum on a dark background. The earth's population is near panic when the astronomer announces the UFO is

The neutral hydrogen atom consists of

If a light-emitting object is moving away from you, you observe its wavelengths to be ________ its wavelengths if it were at rest.

The process of removing an electron from a stable nucleus is known as ____________________.

The number of ____ in the nucleus determines what element the nucleus is.

The process of making an electron less tightly bound to an atom's nucleus is known as

Two white dwarf stars are the same size, but one has a surface temperature twice as hot as the other. The hotter star will radiate

Suppose the laboratory wavelength of a spectral line is 600 nm. In a star it is measured to be 599.4 nm. Is the star moving toward or away from us, relative to the line of sight? How fast is it moving? (Hint: c = 300,000 km/s)

The most massive part of the atom is(are) the which has(have) a charge.

If continuous spectrum light from a star passes through a cool, low-density gas on its way to your telescope and spectroscope, ____ spectrum on the continuous spectrum results.

The figure shows a color image of Betelgeuse, a red giant star. Which of the surface temperatures below best matches Betelgeuse's surface temperature? Hint: Our sun at 6000 K is yellow.

Which of the following is not a fundamental component of the atom?

At what wavelength would a star radiate the greatest amount of energy if the star has a surface temperature of 10,000 K?

Which one of the hydrogen atoms below is EMITTING light at a wavelength in the Balmer series?

In the diagram below, draw the transition that would emit a photon with the smallest wavelength.

The ____________________ of a star can be determined from its color.