Question

Laser produces red light of wavelength 632.8 nm. calculate the energy, in kilojoules, of one mole of photons of this red light.

Answer 1

λ=632.8*10^(-9) ν=v/λ =3*10^8/(632.8*10^(-9)) =4.74083*10^(14) energy of a particle =hν =6.636*10^(-34)*4.74083*10^(14) =3.146*10^(-19)J energy of 1mol of photons =3.146*10^(-19)*6.022*10^23 =1.89*10^5j =1.89*10^2 KJ