Radioactivity

Question 1

Explain why the ACTIVITY of radioactive material is a major factor when considering the safety precautions in the disposal of radioactive waste.

Answer 1

Materials with short half life have initial high activity -> precautions needed for initial period of disposal

Materials with long half life have activity for long period of time -> precautions for long term disposal

Question 2

Define spontaneous

Answer 2

Decay cannot be induced

Question 3

Define random

Answer 3

Decay cannot be predicted

Question 4

Define decay constant

Answer 4

The probability of decay of a nucleus per unit time

Question 5

Explain the technique of radioactive carbon dating

Answer 5

• Living organisms absorb carbon
• Once dead, they stop absorbing carbon
• Measure the number of C14 and C12 nuclei in a living sample and the dead sample
• Use an equation to estimate age

Question 6

When carbon-dating, suggest why the activity is measured over a long period of time.

Answer 6

Decay of the nuclei is random so activity might be low

Question 7

Why is carbon dating not appropriate for finding the age of samples older than 10^5 years?

Answer 7

The activity would be very low so cannot be distinguished by the background activity.