Problem 11-35 Potential and kinematics - Part 2 - B

A proton is accelerated from rest from a positively charged plate to a parallel negatively charged plate. The separation of the plates is \(8.9\; mm.\) If the potential difference between the plates is \(75.3\; V,\) what is the speed of the proton just as it hits the negative plate?
[Ans. \(1.2 \times 10^5\; m/s\)]

Accumulated Solution

Proton diagram B

Let us then use the Energy approach.
The potential energy \(U\) of a charge \(q\) at a location where the potential is \(V\) is:

(A)   \(U = qV\)

(B)   \(U = q/V\)

(C)   \(U = V/q\)