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A sample of a radioactive isotope contains 
nuclei of the isotope at time 
. At time (
), the sample contains (
) nuclei of the isotope. The time interval 
is short. Use the symbols , 
, 
and to give expressions for:
the average activity of the sample during the time ,
the probability of decay of a nucleus in the time ,
the decay constant 
of the isotope.
The isotope polonium-208 (
) is radioactive and decays to form lead-204 (
). The nuclear equation for this decay is
Data for nuclear masses are given in the table below.
Determine, for the decay of one nucleus of polonium-208:
the change, in 
, of the mass
the total energy, in 
, released.
The polonium-208 nucleus is initially stationary. The initial kinetic energy of the 
nucleus (
-particle) is found to be less than the energy calculated in (i) part 2. Suggest two possible reasons for this difference.
.
.
.
.
.
-ray photon
