A proton is launched from point 1 in with an initial velocity of 3.9×10^5 m/s.?

By how much has its kinetic energy changed, in eV, by the time it passes through point 2? Assume negative answer if kinetic energy decreases and positive if kinetic energy increases. ------------------------------------------ My Analysis : KE(I) = 1/2 mv^2 ; mass of proton = 1.672*10^-27kg KE(I) = 3.26*10^-22J At... show more By how much has its kinetic energy changed, in eV, by the time it passes through point 2? Assume negative answer if kinetic energy decreases and positive if kinetic energy increases.
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My Analysis :
KE(I) = 1/2 mv^2 ;
mass of proton = 1.672*10^-27kg
KE(I) = 3.26*10^-22J

At 100 V , delta(V) = W1/q ;
W1 = V*q = 100V*1.602*10^-19C=1.602*10^-17J

W2 = V*q (from 100 to 200) =
100V*1.602*10^-19C=1.602*10^-17J

W1+W2 = 3.2*10^-17J
W=ΔKE
3.2*10^-17J - 1.602*10^-17J =
1.602*10^-17J or 199.975 eV

Is this correct, please help.
1 answer 1