Question

A moving particle encounters an external electric field that decreases its kinetic energy from 9100 eV to 6630 eV as the particle moves from position A to position B. The electric potential at A is -59.5 V, and the electric potential at B is +26.1 V. Determine the charge of the particle. Include the algebraic sign (+ or −) with your answer.

Answer 1

ΔKE=-ΔPE= q•Δφ.
9100-6630=2470 eV=2470•1.6 •10^-19 =3.95 •10^-16 J.
|Δφ|=|φ1- φ2|=|-59.5-26.1|=|-85.6|=85.6 V
q=3.95 •10^-16/85.6 = + 4.62•10^-18 C

Answer 2

Wait this isn't Jacks new video about timelines...