State the name of one kind of radiation detector.
State one safety precaution that the teacher has to take when handling a radioactive source.
State the meaning of random in time.
Describe how the apparatus is used to demonstrate that the emissions are random in time.
State the meaning of background radiation.
Describe how the count rate is adjusted for background radiation.
Determine the greatest distance the radiation travels in air.
State which type of radiation is emitted by the radioactive source, and justify your answer.
As the radiation from the source moves through the air, it causes ionisation. Describe what is meant by ionisation of the air.
The half-life of a second radioactive source is $40\,\text{minutes}$. At the start, the corrected count rate from this source is $300\,\text{counts/min}$. On Fig. 11.3, plot suitable points and draw a graph showing how the corrected count rate changes with time.