AFOQT Practice Test

Which of the following is NOT a component of stars?

1. Gas

2. Plasma

3. Water

4. Light

The correct answer is: Water

The correct answer is that water is not a component of stars. Stars are primarily composed of gases, such as hydrogen and helium, which exist in a state known as plasma. Plasma is a high-energy state of matter where electrons are separated from atoms, and it is the dominant state in stars due to the extreme temperatures and pressures found in stellar environments. Light is also a fundamental aspect of stars. Stars emit light due to the nuclear fusion reactions occurring in their cores, which convert mass into energy according to Einstein’s equation, E=mc². This energy is released as electromagnetic radiation, including visible light. Water, while abundant on Earth, is not found in significant amounts in stars. The conditions within stars do not allow for liquid water or stable molecular forms of H₂O to exist. Thus, when considering the primary components that make up stars, water is not included, making it the correct choice.