SLCC PHYS 1040 – Elementary Astronomy
Practice Exam Questions And Correct
Answers (Verified Answers) Plus Rationales
2025|2026 Q&A | Instant Download Pdf
1. What is the primary source of the Sun’s energy?
a) Chemical combustion
b) Gravitational contraction
c) Nuclear fusion of hydrogen into helium
d) Radioactive decay
The Sun’s energy comes from nuclear fusion in its core, where
hydrogen nuclei combine to form helium, releasing vast amounts of
energy.
2. Which of the following best describes a light-year?
a) A unit of time
b) A unit of distance
c) The time it takes light to circle Earth
, d) The brightness of a star
A light-year measures the distance light travels in one year, about
9.46 trillion kilometers.
3. Which phase of the Moon occurs when the Earth is between the Sun
and the Moon?
a) First quarter
b) New Moon
c) Full Moon
d) Third quarter
A Full Moon occurs when the entire face of the Moon is illuminated,
which happens when Earth lies between the Sun and Moon.
4. The apparent backward motion of a planet against the background
stars is called:
a) Precession
b) Retrograde motion
c) Revolution
d) Rotation
Retrograde motion occurs when Earth overtakes a slower-moving
outer planet, making it appear to move backward temporarily.
5. What causes the seasons on Earth?
a) Distance from the Sun
b) Tilt of Earth’s rotational axis
c) Changes in Earth’s orbit speed
, d) Variation in solar output
Earth’s axis is tilted 23.5°, causing varying sunlight angles and
daylight hours, which create the seasons.
6. Which type of electromagnetic radiation has the shortest wavelength?
a) Infrared
b) Radio
c) Visible light
d) Gamma rays
Gamma rays have the shortest wavelength and highest energy in the
electromagnetic spectrum.
7. What type of telescope uses mirrors to gather light?
a) Refracting telescope
b) Reflecting telescope
c) Radio telescope
d) Infrared telescope
Reflecting telescopes use mirrors instead of lenses to focus light.
8. Which planet has the most prominent ring system?
a) Jupiter
b) Uranus
c) Neptune
d) Saturn
Saturn’s ring system is the most extensive and visible from Earth.
, 9. The Sun is classified as what type of star?
a) White dwarf
b) Red giant
c) G-type main sequence star
d) Neutron star
The Sun is a G2V star, a yellow main-sequence star in the
Hertzsprung-Russell diagram.
10. Which of the following is the largest structure in the universe?
a) Planet
b) Star
c) Galaxy
d) Galaxy cluster
Galaxy clusters are collections of many galaxies bound by gravity,
making them larger than individual galaxies.
11. Kepler’s First Law states that planetary orbits are:
a) Perfect circles
b) Ellipses with the Sun at one focus
c) Spirals
d) Random paths
Kepler showed planets orbit the Sun in elliptical paths, not perfect
circles.
12. Which planet has the longest day (rotation period)?
a) Earth
Practice Exam Questions And Correct
Answers (Verified Answers) Plus Rationales
2025|2026 Q&A | Instant Download Pdf
1. What is the primary source of the Sun’s energy?
a) Chemical combustion
b) Gravitational contraction
c) Nuclear fusion of hydrogen into helium
d) Radioactive decay
The Sun’s energy comes from nuclear fusion in its core, where
hydrogen nuclei combine to form helium, releasing vast amounts of
energy.
2. Which of the following best describes a light-year?
a) A unit of time
b) A unit of distance
c) The time it takes light to circle Earth
, d) The brightness of a star
A light-year measures the distance light travels in one year, about
9.46 trillion kilometers.
3. Which phase of the Moon occurs when the Earth is between the Sun
and the Moon?
a) First quarter
b) New Moon
c) Full Moon
d) Third quarter
A Full Moon occurs when the entire face of the Moon is illuminated,
which happens when Earth lies between the Sun and Moon.
4. The apparent backward motion of a planet against the background
stars is called:
a) Precession
b) Retrograde motion
c) Revolution
d) Rotation
Retrograde motion occurs when Earth overtakes a slower-moving
outer planet, making it appear to move backward temporarily.
5. What causes the seasons on Earth?
a) Distance from the Sun
b) Tilt of Earth’s rotational axis
c) Changes in Earth’s orbit speed
, d) Variation in solar output
Earth’s axis is tilted 23.5°, causing varying sunlight angles and
daylight hours, which create the seasons.
6. Which type of electromagnetic radiation has the shortest wavelength?
a) Infrared
b) Radio
c) Visible light
d) Gamma rays
Gamma rays have the shortest wavelength and highest energy in the
electromagnetic spectrum.
7. What type of telescope uses mirrors to gather light?
a) Refracting telescope
b) Reflecting telescope
c) Radio telescope
d) Infrared telescope
Reflecting telescopes use mirrors instead of lenses to focus light.
8. Which planet has the most prominent ring system?
a) Jupiter
b) Uranus
c) Neptune
d) Saturn
Saturn’s ring system is the most extensive and visible from Earth.
, 9. The Sun is classified as what type of star?
a) White dwarf
b) Red giant
c) G-type main sequence star
d) Neutron star
The Sun is a G2V star, a yellow main-sequence star in the
Hertzsprung-Russell diagram.
10. Which of the following is the largest structure in the universe?
a) Planet
b) Star
c) Galaxy
d) Galaxy cluster
Galaxy clusters are collections of many galaxies bound by gravity,
making them larger than individual galaxies.
11. Kepler’s First Law states that planetary orbits are:
a) Perfect circles
b) Ellipses with the Sun at one focus
c) Spirals
d) Random paths
Kepler showed planets orbit the Sun in elliptical paths, not perfect
circles.
12. Which planet has the longest day (rotation period)?
a) Earth
