CSET CSET Science: Earth and Space Sciences 3

Question 1

What is the primary energy source that powers the Sun?

Accepted Answer

Nuclear fusion of hydrogen nuclei into helium

Answer

The Sun generates energy through nuclear fusion in its core, where hydrogen nuclei fuse to form helium, releasing enormous energy according to E=mc².

Question 2

What does the Hertzsprung-Russell (H-R) diagram plot?

Accepted Answer

Stellar luminosity versus surface temperature

Answer

The H-R diagram plots stars according to their luminosity on the vertical axis and surface temperature on the horizontal axis, revealing patterns in stellar classification and evolution.

Question 3

According to current scientific understanding, what is the approximate age of the universe?

Accepted Answer

13.8 billion years

Answer

Measurements of cosmic microwave background radiation and the universe's expansion rate indicate an age of approximately 13.8 billion years since the Big Bang.

Question 4

What causes the phases of the Moon as observed from Earth?

Accepted Answer

The changing angle from which observers on Earth view the sunlit half of the Moon

Answer

As the Moon orbits Earth, observers see different portions of its sunlit half depending on the geometric angle between the Sun, Moon, and Earth, creating the phases.

Question 5

Which type of galaxy is characterized by a central bulge surrounded by a flat rotating disk with spiral arms?

Accepted Answer

Spiral galaxy

Answer

Spiral galaxies, like the Milky Way, feature a central bulge of older stars surrounded by a flat disk with spiral arms that contain stars, gas, dust, and active star formation.

CSET Test Practice Test

CSET Test Practice Test

CSET CSET Science: Earth and Space Sciences 3