1. Which of the following describes a solar eclipse?
a. the earth is between the sun and the moon, and the earth is in the
moon's shadow
b. the earth is between the sun and the moon, and the moon is in the
earth's shadow
c. the moon is between the earth and the sun, and the moon is in the
earth's shadow
d. the moon is between the earth and the sun, and the earth is in the
moon's shadow
2. What is a light year?
a. a unit of time equal to 6 trillion seconds
b. the average distance between the Earth and the Sun
c. the distance light travels in a year
d. the time the Earth takes to orbit the Sun
3. What is a parsec?
a. a unit of time equal to about 3.26 million seconds
b. a unit of angle equal to 1/3600 of a degree
c. the distance light travels in a year
d. the distance at which the parallax angle is 1 arcsecond
4. That famous observing team of Drs. Harden, Petrie, and Rozyczka measures
the parallaxes of the stars Sirius and Altair. They find that Sirius has
a parallax angle of 0.30 arcsecond, and Altair has a parallax angle of 0.15
arcsecond. What do they conclude?
a. Sirius is twice as far away as Altair
b. Altair is twice as far away as Sirius
c. Sirius is twice as large as Altair
d. Altair is twice as large as Sirius
5. Drs. Harden, Petrie, and Rozyczka have discovered a Cepheid in a distant
galaxy, and want to determine exactly how distant that galaxy is. They
have measured the Cepheid's period and brightness. Can they determine its
distance?
a. yes, by using the period-luminosity relation to find the luminosity,
and with the luminosity and brightness they can find the distance
b. yes, by measuring its trigonometric parallax
c. yes, by measuring the Doppler shift of its spectrum
d. no, they would need to know its radius to do that