Electrostatics
Intermediate
Electric Potential
Source: High school physics (Chinese)
Problem Sets:
Electrostatics
Problem
When a point charge is moved from point M with a potential of 500 V to point N with a potential of 200 V, the electric field does $-6.0 \times 10^{-5}$ J of work.
Find the charge of the point charge.
[Q1] $q = -2.0 \times 10^{-7}$ C
The work $W_{MN}$ done by the electric field when a charge $q$ moves from point M to N is given by the product of the charge and the potential difference $U_M - U_N$.
$$W_{MN} = q(U_M - U_N)$$Solving for the charge $q$:
$$q = \frac{W_{MN}}{U_M - U_N}$$Substituting the given values:
$$q = \frac{-6.0 \times 10^{-5} \text{ J}}{500 \text{ V} - 200 \text{ V}} = \frac{-6.0 \times 10^{-5}}{300}$$ $$q = -2.0 \times 10^{-7} \text{ C}$$