Answer:
3.97 x 10^-19 J
Explanation:
The energy E of a photon is given by:
    E = hf where h = Planck's constant = 4.14 × 10−15 eV · s and f = frequency
In this case, f = 6×10^14s−1, hence, the energy E of one photon of the light would be;
E = 4.14 × 10−15 eV · s x 6×10^14s−1
        =  2.484 eV
Note that:
1 eV = 1.60 × 10−19 J
Hence,
2.484 eV = 2.484 x 1.60 × 10−19 J
       = 3.97 x 10^-19 J