How would I go about this? What is the wavelength (in nanometres) of a photon of light with an energy of 8.14x 10^-18J? Answer in Sig figs?

Answer 1

E = hc/λ

E = energy = 8.14x10^-18 J

h = Planks constant = 6.626x10^-34 J-sec

c = speed of light = 3x10⁸ m/sec

λ = wavelength = ?

Solve for λ:

λ = (6.626x10^-34 J-sec)(m/sec) / 8.14x10^-18 J

λ = 2.44x10^-8 m

Converting this to nanometers we have

λ = 2.44x10^-8 m x 1x10⁹ nm / m = 24.4 nm (3 sig. figs.)