Question

An electron has KE 'k' find its de-broglie wavelength​

Answer 1

Explanation:

The de Broglie wavelength is given by λ = h mv . The rest energy of an electron is about 0.5 MeV and the electrons here have kinetic energies of 15 keV, so the non-relativistic approximation is OK - we can use the rest mass for m. So we need to find the speed.