Radioactivity (unit 4)

Question 1

Name a piece of equipment that is used to detect background radiation

Answer 1

Geiger muller tube

Question 2

Types of radiation

Which is most ionising and penetrating

Answer 2

• Alpha
• Beta
• Gamma
• Alpha - most ionising
• Gamma - most penetrating

Question 3

Charge of a particle

• Alpha
• Beta
• Gamma

Answer 3

• Alpha = 2+
• Beta = +/- 1e (depending on whether it’s an electron or a positron)
• Gamma = No charge

Question 4

What is the particle?

• Alpha
• Beta
• Gamma

Answer 4

• Alpha = Helium nucleus
• Beta = Positron or electron (usually an electron)
• Gamma = High energy photon or EM wave

Question 5

Range in air?

• Alpha
• Beta
• Gamma

Answer 5

• Alpha = 1-5cm
• Beta = 10-100cm
• Gamma = Infinite (obeys the inverse square law)

Question 6

Range in other materials?

• Alpha
• Beta
• Gamma

Answer 6

• Alpha = Stopped by paper
• Beta = Stopped by thin sheets of aluminium
• Gamma = Slowed down by thick blocks of lead

Question 7

Define half life

Answer 7

Half life is the time it takes for half of the nuclei to decay. It’s a constant