EXAMPLE PROBLEM ON OHM'S LAW: The Basic Circuit
An emf source of 6.0V is connected to a purely resistive lamp and a current of 2.0 amperes flows. All the wires are resistance-free. What is the resistance of the lamp?
|The gain of potential energy occurs as a charge passes through
the battery, that is, it gains a potential of =6.0V.
No energy is lost to the wires, since they are assumed to be resistance-free.
By conservation of energy, the potential that was gained (i.e. =V=6.0V)
must be lost in the resistor. So, by Ohm's Law:
R = 3.0
Figure 1 Diagram of the circuit in this problem.