Imagine a point charge with charge of "e" between two plates. The plate above(L) is +100V and the plate below(K) is 0V. What is the electric potential energy of the charged particle if it is moved from K to L?
The answer I have gotten from my lecturer is that since the Electric field strength is constant between two metal plates, the electric potential energy is 0. I, however fail to see the relation between the two conditions. Thanks for the help ;)
The answer I have gotten from my lecturer is that since the Electric field strength is constant between two metal plates, the electric potential energy is 0. I, however fail to see the relation between the two conditions. Thanks for the help ;)
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The GAIN in electric potential energy moving from 0V(K) to 100V(L) = eV = 100e. It is NOT zero.
It would only be zero if moving along a line parallel to, and in between, the plates (an isopotential).
The electric field strength is (approximately) constant between the plates providing the separation is small compared to the plate dimensions.. This simply means there is a constant force. on e, wherever it is in the gap.
So if the plates are a distance d apart:
E = V/d
F = eE = eV/d
Work done moving charge distance d = F x d = (eV/d) x d = eV
It would only be zero if moving along a line parallel to, and in between, the plates (an isopotential).
The electric field strength is (approximately) constant between the plates providing the separation is small compared to the plate dimensions.. This simply means there is a constant force. on e, wherever it is in the gap.
So if the plates are a distance d apart:
E = V/d
F = eE = eV/d
Work done moving charge distance d = F x d = (eV/d) x d = eV
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Electric potential energy cannot be zero for the charge at L.
Electric potential energy of the charge in your question may be assumed to be that of the system including the plates and the charge.Since the plates do not move the potential energy of the system changes only due to the movement of the charge e.In your question even if u do not give that the charge comes from K then also the answer will remain the same(It wud b needed if the electric potential energy difference of the system is asked).
I feel u need an explanation regarding electrostatics:
1)We always define electrostatic or electric potential energy for a system(A part of universe) and not for a single charge.
2)If the electric potential is constant,then the electric field is zero(I feel wat your lecturer said was jst opposite).
Good question
Electric potential energy of the charge in your question may be assumed to be that of the system including the plates and the charge.Since the plates do not move the potential energy of the system changes only due to the movement of the charge e.In your question even if u do not give that the charge comes from K then also the answer will remain the same(It wud b needed if the electric potential energy difference of the system is asked).
I feel u need an explanation regarding electrostatics:
1)We always define electrostatic or electric potential energy for a system(A part of universe) and not for a single charge.
2)If the electric potential is constant,then the electric field is zero(I feel wat your lecturer said was jst opposite).
Good question