Astronomy Test 2

1) From shortest to longest wavelength, which of the following correctly orders the different categories of electromagnetic radiation?

• A) infrared, visible light, ultraviolet, X rays, gamma rays, radio

• B) radio, infrared, visible light, ultraviolet, X rays, gamma rays

• C) visible light, infrared, X rays, ultraviolet, gamma rays, radio

• D) gamma rays, X rays, ultraviolet, visible light, infrared, radio

• E) gamma rays, X rays, visible light, ultraviolet, infrared, radio

2) When an atom absorbs a photon containing energy, any of the following can happen except which?

• A) The atom becomes excited.

• B) The atom is ionized.

• C) An electron moves from an upper energy level to a lower one.

• D) An electron moves from a lower energy level to an upper one.

3) Consider an atom of gold in which the nucleus contains 79 protons and 118 neutrons. What is its atomic number and atomic weight?

• A) The atomic number is 79, and the atomic weight is 197.

• B) The atomic number is 79, and the atomic weight is 118.

• C) The atomic number is 118, and the atomic weight is 197.

• D) The atomic number is 118, and the atomic weight is 79.

4) How can an electron in an atom lose energy to go from a higher energy level to a lower energy level?

• A) It loses kinetic energy.

• B) It releases a photon equal in energy to its own energy drop.

• C) It absorbs a photon equal in energy to its own energy drop.

• D) It loses gravitational potential energy.

• E) It exchanges gravitational potential energy for kinetic energy.

5) You observe a distant galaxy. You find that a spectral line normally found in the visible part of the spectrum is shifted toward the infrared. What do you conclude?

• A) The galaxy is moving away from you.

• B) The galaxy is moving toward you.

• C) The galaxy has very weak gravity.

• D) The galaxy is made purely of hydrogen.

• E) The composition of the galaxy is changing.

6) Suppose the angular separation of two stars is smaller than the angular resolution of your eyes. How will the stars appear to your eyes?

• A) You will not be able to see these two stars at all.

• B) The two stars will look like a single point of light.

• C) The two stars will appear to be touching, looking rather like a small dumbbell.

• D) You will see two distinct stars.

• E) You will see only the larger of the two stars, not the smaller one.

7) Which of the following could not be determined by an observation that uses only spectroscopy?

• A) the chemical composition of a distant star

• B) the speed at which a distant galaxy is moving away from us

• C) the surface temperature of a distant star

• D) the rotation rate of a distant star

• E) the size of a distant galaxy

8) How are wavelength, frequency, and energy related for photons of light?

• A) Longer wavelength means lower frequency and lower energy.

• B) Longer wavelength means higher frequency and lower energy.

• C) Longer wavelength means higher frequency and higher energy.

• D) Longer wavelength means lower frequency and higher energy.

• E) There is no simple relationship because different photons travel at different speeds.

9) What do astronomers mean by light pollution?

• A) Light pollution refers to pollution caused by light industry as opposed to heavy industry.

• B) Light pollution refers to harmful gases emitted by common street lights.

• C) Light pollution refers to light used for human activities that brightens the sky and hinders astronomical observations.

• D) Light pollution refers to the lights that must be used inside major observatories and that make it difficult for astronomers' eyes to adapt to darkness.

• E) Light pollution is another name for sunlight, which makes it impossible to see stars in the daytime.

10) What is meant by spectral resolution?

• A) It is a measure of how much energy an object emits in different parts of the electromagnetic spectrum.

• B) It is a measure of how close two spectral lines can be distinguished.

• C) It is a measure of how close two point sources can be distinguished.

• D) It is the same as angular resolution when applied to telescopes operating at different wavelengths.