The electron moves at a speed of 0.95 s. Determine his energy.

Given:

v = 0.95 * c is the speed of the electron;

m = 9.1 * 10 ^ -31 kilograms – electron rest mass;

c = 3 * 10 ^ 8 m / s – the speed of light in vacuum.

It is required to find the electron energy E.

E = m * c ^ 2 / (1 – v ^ 2 / c ^ 2) ^ 0.5 = 9.1 * 10 ^ -31 * (3 * 10 ^ 8) ^ 2 / (1 – 0.95 ^ 2) ^ 0.5 = 15.1 * 10 ^ -15 / (1 – 0.9) ^ 0.5 = 15.1 * 10 ^ -15 / 0.1 ^ 0.5 = 15.1 * 10 ^ -15 / 0.3 = 50 * 10 ^ -15 = 5 * 10 ^ -16 Joules.

Answer: the energy of an electron is 5 * 10 ^ -16 Joules.