VERSION C

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.

Please put away all electronic devices. You will not need a calculator for this quiz.

SELECT THE BEST ANSWER TO EACH PROBLEM.

1. Neutral helium lines are strongest in the spectra of:
a) F stars.
b) G stars.
c) M stars.
d) K stars.
e) B stars.

e) B stars.

2. Which of the following types of stars have spectra that peak in the UV, according to Wien's Law?
a) M.
b) G.
c) K.
d) O.
e) both K and M.

d) O.

3. If a hydrogen atom has an electron in its ground energy level, what kind of photon is needed to ionize it?
a) ultraviolet.
b) red.
c) blue.
d) infrared.
e) radio.

a) ultraviolet.

4. What is Ejnar Hertzsprung known for?
a) Pioneering the use of plots of luminosity vs. temperature for stars.
b) Re-organizing the spectral sequence ABCDEF... to the sequence used today.
c) Determining that the acceleration of an object is inversely proportional to its mass.
d) Determining that the gravitational force between two objects is inversely proportional to the square of the distance apart.
e) Determining that stars are made up of mostly hydrogen and helium.

a) Pioneering the use of plots of luminosity vs. temperature for stars.

5. A period of 5 - 10 minutes is:
a) Approximately the lifetime of a sunspot.
b) Approximately the lifetime of a granule on the Sun's surface.
c) Approximately the time it takes the Sun to spin once on its axis.
d) Approximately how often the overall magnetic polarity of the Sun reverses.
e) Approximately how often the overall magnetic polarity of the Earth reverses.

b) Approximately the lifetime of a granule on the Sun's surface.

6. Which of the following stars has the coldest photosphere?
a) Pollux (type K0III)
b) Arctaurus (type K2III)
c) 42 Draco (between type K1III and type K2III)
d) Formalhaut (type A3V).
e) Aldebaran (type K5III)

e) Aldebaran (type K5III)

7. In Astronomy, the term `spicule' refers to:
a) The strong red emission line of hydrogen.
b) A very low mass neutral particle created by nuclear reactions in the core of the Sun.
c) Short-lived jets of gas above the photosphere of the Sun.
d) The force that holds the nuclei of atoms together.
e) The shift in the wavelength of light due to the relative motion of the source of light and the observer.

c) Short-lived jets of gas above the photosphere of the Sun.

8. By accurately measuring the positions of stars in the sky over and over again, Astronomers can sometimes determine which property of some stars?
a) distance.
b) velocity through space in the plane of the sky.
c) whether the star is part of a binary star.
d) all of the above.
e) none of the above.

d) all of the above.

9. The Super Kamiokande experiment beneath a mountain in Japan was designed to detect what kind of particle produced in the Sun?
a) Neutrons.
b) Neutrinos.
c) Protons.
d) Positrons.
e) Gamma ray photons.

b) Neutrinos.

10. Stefan's Law (the Stefan-Boltzmann Law) describes:
a) The back-and-forth shift of a star on the sky, due to the Earth's orbit around the Sun.
b) The shift in the position of a star on the sky relative to background stars, due to a true motion of the star through space.
c) For a hot solid or hot dense gas, the increase in the wavelength of the peak of the spectrum with decreasing temperature.
d) An increase in the luminosity of an star due to an increase in its temperature and/or radius.
e) The shifting of the wavelength of the light seen by an observer, due to the relative motion of the observer and the source of light.

d) An increase in the luminosity of an star due to an increase in its temperature and/or radius.

11. Giant stars like Capella (a yellow star about ten times the radius of the Sun) are classified as Luminosity Class:
a) III.
b) I.
c) V.
d) X.
e) XXX.

a) III.

12. An M2I star is:
a) hotter and larger than the Sun.
b) hotter but smaller than the Sun.
c) colder and larger than the Sun.
d) colder and smaller than the Sun.
e) the same temperature as the Sun, but larger.

c) colder and larger than the Sun.

13. The ancient Greek Astronomer Hipparchus:
a) Came up with the formula F = GM(1)M(2)/R² to describe the gravitational force.
b) Invented the magnitude system we use today.
c) Was the first person to plot the luminosity of stars vs. their temperatures.
d) Invented the sequence of stellar spectral types that we use today in modern Astronomy.
e) Was the first person to realize that the acceleration of an object is equal to the force applied to it, divided by its mass.

b) Invented the magnitude system we use today.

14. Which of the following spectral types of stars are colder than type G stars?
a) K,M.
b) O,B.
c) B,F.
d) A,B,O.
e) A,B.

a) K,M.

15. Which of the following is a white dwarf?
a) Proxima Cen.
b) alpha Cen B.
c) the Sun.
d) Sirius B.
e) All of the above.

d) Sirius B.

16. What is the equation lambda(max) = 0.0029/T called?
a) Stefan's Law.
b) Wien's Law.
c) The parallax law.
d) Newton's Second Law.
e) The inverse Square Law of Light.

b) Wien's Law.

17. What's the difference between acceleration and velocity?
a) Acceleration is a change in velocity with time.
b) Acceleration has a direction associated with it, velocity does not.
c) Velocity has a direction associated with it, acceleration does not.
d) Acceleration has units of distance per time, while velocity has units of distance per time².
e) Acceleration and velocity are the same thing.

a) Acceleration is a change in velocity with time.

18. Why does it take so long for the energy produced in the core of the Sun to make its way out of the Sun?
a) The convective cells in the convective layer move very slowly, transporting the energy very slowly.
b) The speed of light is very low in the interior of the Sun because of the strong gravity.
c) Photons do not travel very far without being absorbed, and when they are re-emitted, it is in a random direction.
d) Millions of small black holes throughout the Sun trap the energy.
e) The nuclear reactions in the core produce mostly radio waves, which travel very slowly.

c) Photons do not travel very far without being absorbed, and when they are re-emitted, it is in a random direction.

19. Star A has a magnitude of 1. If Star B has a brightness 100 times less than Star A (i.e., the brightness of Star B is 1/100 times that of Star A), what is the magnitude of Star B?
a) 2.
b) 3.
c) 6.
d) -4.
e) 0.

c) 6.

20. Which layer of the Sun is the thinnest, in kilometers?
a) The radiative zone.
b) The convective zone.
c) The corona.
d) The chromosphere.
e) The photosphere.

e) The photosphere.