A radiation detector is placed on the bench in a laboratory. It detects a background count rate of 40 counts/minute.
State what is meant by background radiation. Suggest one source for it.
A sample containing atoms of the radioactive isotope Polonium-208 is removed from a
lead container and brought close to the detector. The average count rate increases to 890 counts/minute.
When two sheets of paper are inserted between the sample and the detector, the average count rate returns to 40 counts/minute. Polonium-208 is represented by the symbol 
. It decays to an isotope of lead (Pb).
Deduce the type of radiation emitted by polonium-208. Explain your answer.
Write down the nuclide equation for the decay of polonium-208.
