# The maximum kinetic energy of electrons emitted from rubidium when it is illuminated by ultraviolet radiation with

**The maximum kinetic energy of electrons emitted from rubidium when it is illuminated by ultraviolet radiation with a wavelength of 315 nm is 1.78 eV. Determine the work function of electrons from rubidium.**

To find out the work function of electrons emitted from the alkali metal rubidium, we use the formula: h * ν = Aout + Ek, whence we express: Aout = h * ν – Ek = h * C / λuf – Ek.

Const: h – Planck’s constant (h = 6.62607 * 10 ^ -34 J * s); C – the speed of propagation of light (C = 3 * 10 ^ 8 m / s).

Data: λuf – the wavelength of the considered ultraviolet radiation (λuf = 315 nm = 315 * 10 ^ -9 m); Ek – max. kinetic energy of emitted electrons (Ek = 1.78 eV or Ek = 2.848 * 10 ^ -19 J).

Let’s perform the calculation: Aout = h * C / λuf – Ek = 6.62607 * 10 ^ -34 * 3 * 108 / (315 * 10 ^ -9) – 2.848 * 10 ^ -19 ≈ 3.46 * 10 ^ -19 J = 346 sJ.

Answer: The work function of electrons emitted from the alkali metal rubidium is 346 sJ.