Astronomy Practice Test — Easy Level

A free 10-question Astronomy practice test for Science Olympiad, written at invitational level. Every question and answer choice is listed below — correct answers and scoring are revealed when you take the timed test.

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Medium (18 questions)

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1. On a Hertzsprung–Russell (H-R) diagram with temperature on the horizontal axis, how is the temperature scale arranged?

A.A) Temperature increases from left to right
B.B) Temperature increases from right to left
C.C) Temperature increases from bottom to top
D.D) Temperature increases from top to bottom

2. Which spectral type corresponds to the hottest main-sequence stars?

A.A) A-type stars
B.B) G-type stars
C.C) O-type stars
D.D) M-type stars

3. What is the final evolutionary stage for a Sun-like star (about 1 solar mass)?

A.A) Neutron star
B.B) White dwarf
C.C) Black hole
D.D) Brown dwarf

4. A nearby star has a measured parallax angle of 0.20 arcseconds. What is its distance from Earth?

A.A) 0.20 parsecs
B.B) 2.0 parsecs
C.C) 5.0 parsecs
D.D) 10.0 parsecs

5. According to Kepler’s Third Law in the simplified form P² = a³ (with P in years and a in AU), what is the orbital period of a planet with a semi-major axis of 4 AU?

A.A) 2 years
B.B) 4 years
C.C) 8 years
D.D) 16 years

6. A galaxy with smooth, featureless light, a rounded shape, and little gas and dust is most likely which type?

A.A) Spiral galaxy
B.B) Elliptical galaxy
C.C) Barred spiral galaxy
D.D) Irregular galaxy

7. Which planets in our solar system are classified as gas giants?

A.A) Mercury and Venus
B.B) Earth and Mars
C.C) Jupiter and Saturn
D.D) Uranus and Neptune

8. A distant galaxy is observed to be moving away from us at 7000 km/s. Assuming Hubble’s constant H₀ ≈ 70 km/s/Mpc, about how far away is the galaxy?

A.A) 10 Mpc
B.B) 50 Mpc
C.C) 70 Mpc
D.D) 100 Mpc

9. In a main-sequence star like the Sun, what is the primary energy source in the core?

A.A) Fusion of helium into carbon
B.B) Fusion of hydrogen into helium
C.C) Radioactive decay of heavy elements
D.D) Gravitational contraction of the outer layers

10. Two stars have the same apparent magnitude as seen from Earth, but Star X is much closer than Star Y. What can you conclude about their absolute magnitudes?

A.A) Star X has a lower (more negative) absolute magnitude than Star Y
B.B) Star Y has a lower (more negative) absolute magnitude than Star X
C.C) Star X and Star Y must have the same absolute magnitude
D.D) There is no relationship between apparent and absolute magnitude