(b) Energy of a photon, E=hv; where, v= frequency =3×1012Hz Therefore, energy =6.6×10−34×3×1012Hz=1.9878×10−21J 1 mole =6.02×1023 photons, therefore, ‌
1
2
mole =3.01×1023 photons Therefore, energy of ‌
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mole of photons ‌‌=1.9878×10−21×3.01×1023 ‌‌=0.5982kJ∕mol