6.1.4 - Half-Life

Question 1

What is half-life?

Answer 1

The time taken for half of the original atoms to decay.

OR

A measure of the time it takes for the count rate to drop by half of the original rate.

Question 2

The probability that any one nucleus decays in one second is fixed, what does this mean for decay?

Answer 2

It is random.

Question 3

The probability that any one nucleus decays in one second is fixed, what does this mean for half-life?

Answer 3

It is constant.

Question 4

What is the count rate?

Answer 4

The radiation measured by the Geiger counter that is emitted per second.

Question 5

What is the count rate measured in?

Answer 5

Becquerels (Bq).

Question 6

What is the net decline?

Answer 6

Ratio of final to initial activity.

Question 7

If the first half-life’s net decline is 1:2, what will it be after to half-lives?

Answer 7

1:4

Question 8

What does it mean if after 3 half-lives, the ration equals 1/8?

Answer 8

1/8th of the material is still radioactive.