Question

Calculate the frequency and the energy of blue light that has a wavelength of 400 nm (h = 6.62 x 10^-34 j-s).

Answer 1

c = λ ν (wavelength * frequency)

ν = 3.00E8 / 400E-9 = 1.20E15 / sec

E = h ν = 6.62E-34 J-s* 1.20E15 / s = 7.94E-19 J

Note: 1 electron volt = 1 * 1.60E-19 = 1.60E-19 J