Nuclear fusion _________________________________.

A. occurs when a nucleus splits
Incorrect. This is nuclear fission.

B. produces hydrogen nuclei
Incorrect. Nuclear fusion often fuses hydrogen nuclei together to produce helium.

C. takes place in the sun
Correct! Nuclear fusion reactions occurring in the sun have provided Earth with energy for billions of years.

D. A, B, and C are correct.
Incorrect. Only one of the above choices is correct, not all of them.

What happens to an atomic nucleus during nuclear fission?

A. It absorbs a second nucleus.
Incorrect. This is nuclear fusion.

B. It splits into one small piece and one large piece.
Incorrect. When a nucleus splits, it forms pieces of similar size.

C. It splits into many small pieces.
Incorrect. When a nucleus splits, it generally forms few pieces.

D. It splits into two pieces.
Correct! Nuclear fission splits an atom into two fragments of about the same size.

A. Alpha decay
Incorrect. Although an alpha particle is present, it is forms by the fusing of the reactants, not by decay.

B. Beta decay
Incorrect. No beta particle is present.

C. Nuclear fission
Incorrect. A nuclear fission reaction would show a large nucleus being split into two pieces.

D. Nuclear fusion
Correct! This reaction show two hydrogen atoms being fused together to form a helium atom.

Which of the following is an example of nuclear fusion?

A. Helium-6 breaks down into a beta particle and lithium-6.
Incorrect. This is a description of beta decay.

B. Hydrogen-1 and hydrogen-2 combine to form helium-3.
Correct! This is describing nuclear fusion.

C. Plutonium-240 decays into uranium-236 and an alpha particle.
Incorrect. This is a description of alpha decay.

D. Uranium-235 and a neutron produce barium-141, krypton-92, and three neutrons.
Incorrect. This is a description of nuclear fission.