Question

The wave length of a wave is 100nm then find its frequency

Answer 1

A photon is a quantum of EM radiation. Its energy is given by E = hf and is related to the frequency f and wavelength λ of the radiation by

E

=

h

f

=

h

c

λ

(energy of a photon)

,

where E is the energy of a single photon and c is the speed of light. When working with small systems, energy in eV is often useful. Note that Planck’s constant in these units is h = 4.14 × 10−15 eV · s.

Since many wavelengths are stated in nanometers (nm), it is also useful to know that hc = 1240 eV · nm.

These will make many calculations a little easier.