What does the Hertzsprung-Russell diagram primarily show?

• The distance of stars from Earth

• The relationship between a star's luminosity and temperature

• The age of stars

• The chemical composition of stars

In which region of the Hertzsprung-Russell diagram are main sequence stars found?

• Top right

• Bottom left

• Diagonal from top left to bottom right

• Centre

What is the first stage in the star formation process?

• Red giant phase

• Main sequence phase

• Protostar formation

• Supernova explosion

Which of the following is a characteristic of main sequence stars?

• They are always red in colour

• They are in a stable phase of nuclear fusion

• They have exhausted their nuclear fuel

• They are the largest stars in the universe

What happens to a star when it becomes a red giant?

• It shrinks and becomes hotter

• It expands and cools down

• It explodes as a supernova

• It turns into a black hole

Which process powers the energy output of main sequence stars?

• Nuclear fission

• Chemical reactions

• Nuclear fusion

• Gravitational contraction

What is the primary element being fused in the core of a main sequence star like the Sun?

• Helium

• Carbon

• Hydrogen

• Oxygen

What is the final stage of a low-mass star's life cycle?

• Black hole

• Neutron star

• White dwarf

• Red supergiant

Which of the following best describes a supergiant star?

• A small, dense star

• A very large and luminous star

• A star that is no longer undergoing fusion

• A star that is about to become a black hole

What is the primary factor that determines the life cycle of a star?

• Its colour

• Its temperature

• Its mass

• Its distance from Earth