For each photon:
e = hν (h:Planck constant; v:frequency)
= hc/λ (c:speed of light; λ:wavelength = 2.669*10^3 m )
For 2.62x10^-1 mole of its photons:
E = Ne (N:number of photons)
= nNa*e (Na:Avogadro constant; number of particles in 1 mol)
= nNa*hc/λ
= 2.62*10^(-1) *6.02*10^23 * 6.63*10^(-34) *3.00*10^8/2.669*10^3
= 1.18*10^(-5) J