From what i know, when a charge moves in the direction of the electric field, work is done by the charge and its potential energy decreases. So similarly, when a charge move against the electric field, work is done on the charge.
Okay here are the textbook questions:
Determine if work was done on the field or by the field or no work is done for each of the following charged objects in a uniform electric field.
a) An electron moves towards a positive plate.
answer: by the field.
Shouldnt this be work done on the field by the charge since the electron is going with nature?
c) A proton moves towards a positive plate.
answer: on the field.
Shouldnt this be the opposite instead? the proton is going against nature?? and work is done to increase its potential energy?
Am i missing something?
Best Answer
An electron in electric field has tendency to move opposite to the electric field. If it does so the work done by the field force is positive as the force on electron and direction of its movement is in same direction. More simply If the electron is in electric field the field pushes it towards the positive plate
From what i know, when a charge moves in the direction of the electric field, work is done by the charge and its potential energy decreases. So similarly, when a charge move against the electric field, work is done on the charge. This statement is wrong as-
1.No work can ever be done by the charge. Work is either done by the electric field or some external force.
I have already answered the electron part above.Coming to the second part as I said the proton should move towards negative plate, but since it moves towards the positive plate some external force must have done work against electric field. Hence the work is done on electric field.