Electron problem-potential difference and kinetic energy

Question

An electron with an initial speed of 5.50×10⁵ m/s is brought to rest by an electric field.

What was the potential difference that stopped the electron?

What was the initial kinetic energy of the electron, in electron volts?

Answer 1

0 - mv²/2 = e·ΔU; ΔU = - mv²/(2e) = - 9.11·10^-31kg·5.5²·10¹⁰m²/s²/(-2·1.6·10^-19C) = 0.86 V

K = eΔU = 0.86 eV