Version A

Write your name at the top of this quiz as well as on your answer sheet. WRITE YOUR VERSION ON YOUR ANSWER SHEET. Feel free to write or draw on the quiz.

THERE IS ONLY ONE CORRECT ANSWER PER PROBLEM.

1. Which of the following types of light has the highest frequency?
a) Gamma rays.
b) Visible light.
c) Radio waves.
d) Infrared light.
e) Ultraviolet light.

a) Gamma rays.

2. A Hertz is a:
a) joule/sec.
b) calorie/sec.
c) m/s².
d) 1/sec.
e) kilowatt-hour.

d) 1/sec.

3. Microwaves are:
a) ultraviolet light.
b) infrared light.
c) gamma rays.
d) X-rays.
e) radio waves.

e) radio waves.

4. The filament in an ordinary light bulb produces:
a) an emission-line spectrum.
b) an absorption-line spectrum.
c) a continuous spectrum.
d) a bright-line spectrum.
e) a dark-line spectrum.

c) a continuous spectrum.

5. Refraction of light is caused by:
a) atoms being ionized.
b) atoms being excited.
c) a relative motion of the source of light and the observer.
d) the speed of light always being a constant, no matter what kind of material the light is moving through.
e) the speed of light changing when light travels from one medium into another.

e) the speed of light changing when light travels from one medium into another.

6. Star A has a surface temperature 1/3rd that that of Star B. Therefore, the wavelength of the peak of the spectrum of Star A is:
a) three times larger than that of Star B.
b) 1/3 that of Star B.
c) nine times larger than that of Star B.
d) 1/9th that of Star B.
e) the same as that of Star B.

a) three times larger than that of Star B.

7. Atom A has 6 electrons, 6 protons, and 6 neutrons. Atom B has 5 electrons, 6 protons, and 7 neutrons. Therefore:
a) Atom A has a mass approximately 12/11 times larger than Atom B.
b) Atom A is a carbon atom; Atom B is a boron atom.
c) Atom A and Atom B have the same mass, but different net charges.
d) Atom A and Atom B have different masses, but the same net charge.
e) Atom A and Atom B have different masses and different net charges.

e) Atom A and Atom B have different masses and different net charges.

8. According to Kirchoff's Laws, what produces an absorption-line spectrum?
a) a low density gas.
b) a hot solid.
c) a hot dense gas.
d) a hot solid or hot dense gas behind a low density gas.
e) a vapor lamp.

d) a hot solid or hot dense gas behind a low density gas.

9. In which of the following types of telescopes is the detector (and sometimes the Astronomer) placed in front of the primary mirror, blocking some of the incoming light?
a) A refracting telescope.
b) A Newtonian Focus telescope.
c) A Coude Focus telescope.
d) A Cassegrain Focus telescope.
e) A Prime Focus telescope.

e) A Prime Focus telescope.

10. An isotope is:
a) An atom which has lost an electron.
b) An atom which has an electron that has jumped to a higher energy level.
c) An atom which has emitted a photon of light.
d) An atom which has a different number of neutrons than another atom of the same element.
e) An atom which has an extra electron.

d) An atom which has a different number of neutrons than another atom of the same element.

11. Star A has a mass of M₁, and Star B has a mass of M₂. Star A's distance from the center of mass of the pair is X₁, while Star B's distance from the center of mass is X₂. The equation that relates these four quantities is:
a) X₁X₂ = M₁M₂.
b) M₁X₁² = M₂X₂².
c) M₁X₁ = M₂X₂.
d) M₁/X₁ = M₂/X₂.
e) M₁X₁³ = M₂X₂³.

c) M₁X₁ = M₂X₂.

12. As a planet orbits around a star in an elliptical orbit, which of the following remains a constant?
a) the velocity.
b) the speed.
c) the kinetic energy.
d) the potential energy.
e) the total energy.

e) the total energy.

13. From laboratory measurements, we know that the H-beta spectral line of hydrogen appears at a wavelength of 486 nm. The spectrum of a particular star shows this line appearing at a longer wavelength of 490 nm. What can we conclude?
a) The star is moving towards us.
b) The star is moving away from us.
c) The star is getting hotter.
d) The star is getting colder.
e) The `star' is actually a planet.

b) The star is moving away from us.

14. The Earth has a temperature of about 300K, while the temperature of the photosphere of the Sun is 6000K, and that of Betelgeuse is 3000K. The thermal spectrum of the Earth peaks in the:
a) visible.
b) X-ray.
c) ultraviolet.
d) infrared.
e) gamma ray.

d) infrared.

15. A hot burner on a stove glows a reddish color. This is because of:
a) strong emission from the H-alpha line of hydrogen.
b) a redshift.
c) thermal radiation.
d) strong absorption lines in the blue part of the spectrum, making it look red.
e) the refraction of light.

c) thermal radiation.

16. 273 degrees Kelvin is:
a) The boiling point of water.
b) The freezing point of water.
c) Absolute zero.
d) The temperature of the photosphere of the Sun.
e) 212 degrees Fahrenheit.

b) The freezing point of water.

17. What causes refraction, the bending of a ray of light when it goes from one medium to another?
a) a Doppler shift.
b) the speed of light is different in the two substances.
c) Wien's Law.
d) Stefan's Law.
e) a change in the frequency and wavelength of the light, but not the velocity.

b) the speed of light is different in the two substances.

18. For which kind of telescope is chromatic aberration a problem?
a) A Newtonian telescope.
b) A Prime Focus telescope.
c) A refracting telescope.
d) A Cassegrain focus telescope.
e) For all kinds of telescopes.

c) A refracting telescope.

19. Coude Focus telescopes are sometimes used for spectroscopy. These telescopes have:
a) Primary lens rather than primary mirrors.
b) The detector directly in front of the primary mirror.
c) The eyepiece or detector mounted on the side of the telescope tube.
d) The eyepiece or detector mounted on the back of a primary mirror.
e) Both a secondary and a tertiary mirror, so that the light rays can be deflected to the same location no matter where in the sky the telescope is pointed.

e) Both a secondary and a tertiary mirror, so that the light rays can be deflected to the same location no matter where in the sky the telescope is pointed.

20. Ionization is:
a) The bending of a light ray when it goes from one substance to another.
b) When parallel light rays are reflected from a curved mirror to single focal point.
c) When an electron in an atom jumps up to a higher energy level in the atom.
d) When an electron escapes from an atom.
e) When an electron in an atom jumps to a lower energy level, closer to the nucleus.

d) When an electron escapes from an atom.