Question
The energy of a photon is given as $$3.03 \times {10^{ - 19}}J.$$ The wavelength of the photon is
A.
6.56$$\,nm$$
B.
65.6$$\,nm$$
C.
0.656$$\,nm$$
D.
656$$\,nm$$
Answer :
656$$\,nm$$
Solution :
$$\eqalign{
& E = \frac{{hc}}{\lambda }\,\,\,{\text{or}}\,\,\,\lambda = \frac{{hc}}{E} \cr
& \lambda = \frac{{6.626 \times {{10}^{ - 34}}J\,\,s \times 3 \times {{10}^8}m\,\,{s^{ - 1}}}}{{3.03 \times {{10}^{ - 19}}J}} \cr
& \,\,\,\,\, = 6.56 \times {10^{ - 7}}m\,\,\,{\text{or}}\,\,\,656\,nm \cr} $$