Question

If the minimum energy (work function) required to eject an electron from a copper surface by the photoelectric effect is 6.45 ✕ 10−19 J, what is the wavelength (in nanometers) of a photon of that energy?

Answer 1

\[E _{photon} = \frac{hc}{\lambda}\]
Where h is Planck's Constant, c is the speed of light, and lambda is the wavelength in meters.

Answer 2

Wavelength = 3.0 * 10^8 m/s* 6.63 * 10^-34 Js / 6.45 *10^-19 J
Roughly answer is 300 nm