How much work does the electric field do in moving a proton from a point with a potential of +125 v to a point where it is -55 v? express your answer both in joules and electron volts?

The work W done by the electric field in moving the proton is equal to the difference in electric potential energy of the proton between its initial location and its final location, therefore:

where q is the charge of the proton, , with  being the elementary charge, and  and  are the initial and final voltage.

Substituting, we get (in electronvolts):

and in Joule: