The voltage applied to an X-ray tube is `18 kV`. The maximum mass of photon emitted by the X-ray tube will be

Options

A. `2 xx 10^(-13) kg`
B. `3.2 xx 10^(-36) kg`
C. `3.2 xx 10^(-32) kg`
D. `9.1 xx 10^(-31) kg`

Answer

C

Explanation

Energy photon is given by `m c ^(2)`. Now, the maximum energy of photon is equal to the maximum energy of electrons = eV Hence, `m e ^(2) = e V`
implies `m = (e V)/( c^(2)) = (1.6 xx 10^(-19) xx 18 xx 10^(3))/((3 xx 10^(8))^(2)` `= 3.2 xx 10^(-32) kg`