So we want to know the energy of a photon that has a frequency f=5.2*10^14 Hz. The equation for energy of a photon is E=h*f where E is energy, h= 6.63*10^-34 is the Planck's constant and f is the frequency. So lets input the numbers:
E=h*f= (6.63*10^-34)*(5.2*10^14)=
E=(6.63*5.2)*10^(-34+14)= 34.478*10^-20=3.4478*10^-19 J.
So a photon has the energy E=3.4478*10^-19 J.
