Solution :
Energy (E) of a photon is given by the expression, E=hν
Where, h = Planck’s constant = $6.626 \times 10^{–34}\; Js$
ν = frequency of light =$ 3 \times 10^{15} Hz$
Substituting the values in the given expression E = hv we get
$E = (6.626 \times 10^{–34}) (3 \times 10^{15})$
$E = 1.988 \times 10^{–18} J$