- From the definition of potential difference, the electrical work done is given by the equation
W = QV,
where
W = work
Q = charge
V = potential difference
- Since the work done must be equal to the energy to do the work, therefore we can also say that, the electrical energy ( E ) is also given by the formula
Example
Given that the potential difference across a bulb is 240V and the current that flow through the bulb is 0.25A. Find the energy dissipated in the bulb in 30s.
Answer:
Formula of current,
E = QV
hence
Q = It
Energy dissipated,
E = QV
E = (It)Q
E = (0.25)(30)(240)
E = 1800V
Given that the potential difference across a bulb is 240V and the current that flow through the bulb is 0.25A. Find the energy dissipated in the bulb in 30s.
Answer:
Formula of current,
E = QV
hence
Q = It
Energy dissipated,
E = QV
E = (It)Q
E = (0.25)(30)(240)
E = 1800V