Frequency of radiation (ν),
`v = (1)/(2.0 xx 10^(-9)s)`
`v = 5.0 xx 10^(8) s^(-1)`
Energy (E) of source `= Nhv`
Where,
N = number of photons emitted
h = Planck’s constant
ν = frequency of radiation
Substituting the values in the given expression of (E):
`E = (2.5 xx 10^(15))(6.626 xx 10^(-34)Js)(5.0 xx 10^(8) s^(-1))`
`E = 8.282 xx 10^(-10) J`
Hence, the energy of the source (E) is `8.282 × 10^(-10)` J.