DeAnza College

ASTRONOMY

Practice Exam, Mr. Harrington's sections

NOTE: On the midterm exam (for which you will use a "Parscore" answer sheet), you will fill in the "A" bubble if the choice is true; you will fill in the "B" bubble if it is false. You will have to fill in "A" or "B" for each choice.

On this practice test, just mark each choice either true [T] or false [F]. At least one answer in each question group is correct ("true"), but any number of choices from one to all of them can be correct. You should treat each numbered answer as a separate true-false question; if it is a correct answer to the question or a correct completion of the statement mark it "true", if it's not then mark it "false".

Correct answers are indicated in large, bold-face type.

A. Which of the following is/are contribution(s) made by Galileo Galilei to science?
T
F 1) The finding that a planet's distance from the Sun is related to its orbital period. (Kepler did that, not Galileo.)
T F 2) The discovery of four moons of Jupiter.
T F 3) The discovery of the phases of Venus.
T F 4) The discovery that the Milky Way consists of numerous faint stars.

B. You write your home address in the order of street, town, state, and so on. Suppose you were writing your cosmic address in a similar manner. Which of the following is the correct order?
T
F 5) Earth, Milky Way Galaxy, Solar System, Local Group
T F 6) Earth, Solar System, Milky Way Galaxy, Local Group
T
F 7) Solar System, Earth, Local Group, Milky Way Galaxy
T
F 8) Solar System, Earth, Milky Way Galaxy, Local Group

C. An Astronomical Unit is
T F 9) the average distance from Earth to the Sun.
T
F 10) the average distance from Earth to the Moon.
T
F 11) slightly longer than a light year.
T F 12) much shorter than a light year. (Remember that the light year is used for expressing interstellar distances, which are vastly larger than the interplanetary distances for which the AU is used.)
T F 13) the semi-major axis of Earth's orbit. (The semi-major axis of a planet's orbit is what is meant by its "average distance" from the Sun -- see chapter 4.)

D. The term "retrograde motion" for a planet's apparent motion (as seen from Earth) through the constellations refers to
T
F 14) the north-south motion of a planet (as opposed to its usual east-west motion).
T
F 15) the apparent west to east motion of a planet as seen by an observer on the Earth due to the Earth's rotation.
T F 16) its occasional motion from east to west relative to the background of the stars.
T F 17) a reversal in the apparent direction of motion of a planet against the background of the stars as seen from Earth. (See figure 4-15 on page 62 of your textbook.)

E. If you move, then nearby things appear to shift their positions against the background. This phenomenon is called
T
F 18) proper motion.
T
F 19) translation of image.
T F 20) parallax.
T
F 21) inversion.

F. What causes the seasons?
T
F 22) Earth is closer to the Sun in the summer than it is in the winter.
T
F 23) Earth's orbit is elliptical. (NOTE: Earth's orbit is elliptical, of course, but that is not the cause of the seasons. Remember, in order to mark a choice "true" it has to be a correct answer to the question or a correct completion of the statement.)
T F 24) Earth's axis is tilted relative to a perpendicular to its orbit plane.
T
F 25) The Sun gets slightly brighter and dimmer with a one-year period.

G. Which of the following is/are characteristics that all of the major planets in our solar system share?
T F 26) They orbit around the Sun in about the same plane.
T F 27) They orbit around the Sun in the same direction.
T F 28) They have very nearly (but not quite) perfectly circular orbits.
T
F 29) They are all made almost entirely of hydrogen and helium. (Only the Jovian planets are made almost entirely of hydrogen and helium.)

H. Which one(s) of the following believed in the heliocentric model of the solar system?
T F 30) Copernicus
T F 31) Galileo
T F 32) Kepler
T
F 33) Everyone did, up until about 400 years ago. (This would have been the only "true" answer if the question had asked who believed in the geocentric model.)

I. What's the difference between a 2nd magnitude star and a 5th magnitude star?
T F 34) The 2nd magnitude star is brighter.
T
F 35) The 5th magnitude star is brighter.
T
F 36) The 2nd magnitude star is more massive. ("Magnitude" refers only to brightness and not to any other property of a star.)
T
F 37) The 5th magnitude star is more massive.

J.  Which of the following is/are Jovian planets?
T F  38) Jupiter
T
F  39) Mars  (Mars is a Terrestrial planet.)
T
F  40) Pluto  (Pluto is a Kuiper Belt Object.)

Scoring:

Your percentage score on the exam would be the total number of answers you evaluated correctly divided by 40 (and multiplied by 100, of course.)

Example: If you answered 30 of the true-false choices correctly, then your percentage score would be 75. Your percentage grade is what is recorded for each exam.