Problem 3.375

An electron starts moving in a uniform electric field of strength $E=10 \mathrm{kV} / \mathrm{cm} .$ How soon after the start will the kinetic energy of the electron become equal to its rest energy?

t=\frac{\sqrt{T\left(T+2 m_{0} C^{2}\right)}}{c e E}=3.0 \mathrm{~ns}

Motion of Charged Particles in Electric and Magnetic Fields