Point A is at a potential of +270 V, and point B is at a potential of -130 V. An α-particle is a helium nucleus that contains two protons and two neutrons; the neutrons are electrically neutral. An α-particle starts from rest at A and accelerates toward B. When the α-particle arrives at B, what kinetic energy (in electron volts) does it have?

1 answer

(delta) V=EPE/q
400V = EPE/q
400V*q = Ekfinal (in J)
400V*3.2x10^(-19) (the charge of two protons in helium nucleus) = Ekfinal (in J) = 1.28x10^(-16) J

Convert this to eV (divide by the charge on 1 electron), and you get 800