Question

What is the energy in joules of a mole of photons associated with red light?

Answer 1

Red light is a range of visible ligth, which is from the electromagnetic spectrum

620–750 nm or 620-750 *10^-9 m

Calculate:

E = hc/WL

h = 6.626*10^-34 planck constant

c = 3*10^8 speed of light

WL = wavleenght

therefore

E = ( 6.626*10^-34)(3*10^8) /(620*10^-9 ) = 3.2061*10^-19 J per photon

Per mol --> E = E*NA = (3.2061*10^-19 )(6.022*10^23) = 193071.342 J per mol of photon

Apply same for high end

E = ( 6.626*10^-34)(3*10^8) /(750*10^-9 ) = 2.65*10^-19 J per photon

Per mol --> E = E*NA = (2.65*10^-19 )(6.022*10^23) = 159583 J per mol of photon