Question

A nucleus emits a gamma ray of energy 0.511 MeV from a state that has a lifetime of 1.5 ns. What is the uncertainty in the energy of the gamma ray? (give units of eV)

Answer 1

We know that, the energy of a gamma ray is 0.511 MeV.

The uncertainty in the energy of a gamma ray which will be given by -

= (hbar) / = (hbar)

= (hbar) ln(2) / t1/2

= [(4.135 x 10-15 eV.s) (0.6931)] / (1.5 x 10-9 s)

= [(2.865 x 10-15 eV.s) / (1.5 x 10-9 s)]

= 1.91 x 10-6 eV