Electric Potential Physics Example 4

Follow the full solution, then compare it with the other examples linked below.

hard

A uniform electric field of

E = 500 \text{ N/C}

exists between two parallel plates separated by

d = 0.02 \text{ m}

. (a) What is the potential difference between the plates? (b) How much work is done moving a proton (

q = 1.6 \times 10^{-19} \text{ C}

) from the negative to the positive plate?

1
(a) $V = Ed = 500 \times 0.02 = 10 \text{ V}$ .
2
(b) Work = $qV = 1.6 \times 10^{-19} \times 10 = 1.6 \times 10^{-18} \text{ J}$ .
3
This work is done against the electric force (the proton naturally moves from high to low potential, so moving it the other way requires external work).

Answer

(a)\; V = 10 \text{ V}; \quad (b)\; W = 1.6 \times 10^{-18} \text{ J}

In a uniform field,

V = Ed

gives the potential difference. The work-energy theorem for charges states

W = qV

— this is the basis for electron-volt energy units in particle physics.

About Electric Potential

The electric potential energy per unit charge at a point in an electric field. Measured in volts (V).

What is the electric potential [formula] from a point charge of [formula]? Use [formula].

How much work is needed to move a [formula] charge from a point at [formula] to a point at [formula]

An electron ([formula]) is accelerated through a potential difference of [formula]. What kinetic ene