We have the kinetic energy of an electron accelerated through a potential difference of V volts is given by the equation:
Ek = 1/2mv2 = eV where e is the electron charge (1.6x10-19 C)
The mass of an electron = 9.11 x 10-31 kg
and so v = √(2eV/m) = √(2x1.6x10-19x100/9.11 x 10-31) = 5.92x106 m/s
Therefore: wavelength = h/mv = h/[9.11x10- 31x5.92x106]
= 6.63x10-34/[9.11x10- 31x5.92x106]
= 0.12 x 10-9 m
