Revision - Unit 7 - Radioactivity

Background radiation is ... level ionising radiation.

• low

• high

Which radiation has the fastest speed?

• Alpha

• Beta

• Gamma

What is a moderator in a nuclear reactor?

• It slows down the chain reaction to ensure safety.

• It slows down the neutrons to increase the likelihood of collisions.

What is the critical mass?

• The minimum mass of a fissile substance required to create a chain reaction.

• The minimum atomic mass required to create a chain reaction.

What do the control rods do?

• They slow down the neutrons to increase the likelihood of collisions.

• They absorb the extra neutrons.

Where does most of the sun's energy come from?

• Fission

• Fusion

• Radioactive decay

Where does most of Earth's internal energy come from?

• Fission

• Fusion

• Radioactive decay

Where does the energy from a nuclear reaction come from?

• It comes from a chemical reaction.

• Some mass is converted to energy.

Fission is (1)

Fusion is (2)

• 1) splitting apart

  2) joining together

• 1) joining together

  2) splitting apart

What is used to detect radiation?

• A Geiger counter

• A seismometer