Question

What is the momentum of a photon that has a wavelength of 3.00 102 nm? remember the wavelength of a photon is equal to planck's constant divided by the photon's momentum?

Answer 1

De Broglie's equation is used to show that photons have both particle and wave nature. photons are quantized packets of energy. the wave nature of photons can be proven as they have a wavelength. the particle nature is given by them having both velocity and mass. 
de Broglies equation is;
λ = h / p 
where λ - wavelength 
h - Planck's constant 
p - momentum 
substituting the values in the equation 
p = h/λ
$p = \frac{6.626 * 10^{-34}m^{2} kg/s }{3.00 * 10^{-7} m}$
p  = 2.20 x 10⁻²⁷ kgm/s
momentum of photon is 2.20 x 10⁻²⁷ kgm/s