Lesson 7 + 8 - Half Life

sounds like the title to a fall out game to be honest

What is the activity of a source?

the rate of decay

What is the rate of decay?

the number of decay in one second

What is the unit used for activity?

Bq (Becquerels)

What equipment would we need to measure activity?

Geiger tube and counter and a stopwatch

What is the equation for activity?

Activity (Bq) = nb of counts / time (s)

What affects how active a source is?

• Which substance (i.e. plutonium, uranium)

• The mass (more mass means more activity)

What happens over time to a source?

it becomes less active and fewer decay happen in one second

What are the two meanings of half life of a radioactive isoptope?

• the average time taken for the activity of the sample to half

• the average time taken for half of the original number of nuclei in the sample to decay

What does each radioactive isotope have?

a unique half life

Is radioactive decay random?

yes

Why is radioactive decay random?

it is impossible to predict which nucleui will decay next or the exact time when a specific nuclei decays.

How can you find the half life from a graph?

reading from the graph the time taken for the count rate to halve

What happens after one half life?

the number of radioactive nuclei and the activity halves