Question

if you moved a proton following one of your electric field lines,

a. would there be any work done and

b. how would the energy of the proton change?

Answer 1

a) Field is along the field lines. And force on proton will be along the field. So electric force on proton will be along the field lines and if you move it along a field line, positive work will be done by the electric field.

b) Energy of the proton will decrease as U = -W_electric, since W_electric > 0,  U < 0 , so energy of the proton will decrease.

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