Electromotive Force, or emf, is a crucial concept in understanding how batteries, or cells, function within an electrical circuit. It represents the energy provided by the battery per coulomb of charge. Unlike the potential difference, which can vary, the emf is considered a constant value representing the maximum potential that the source can provide.
In essence, emf is the ability of a battery or generator to push electrons around a circuit, akin to the force that makes a pump move water through pipes. This is why it's often labeled as a force—even though it technically isn't one in the traditional physics sense.
- Measured in volts (V), emf is denoted by the symbol \( \mathcal{E} \).
- It's calculated using the equation: \( \mathcal{E} = V + Ir \), where \( V \) is the terminal voltage, \( I \) is the current, and \( r \) is the internal resistance.
- In the context of the problem, the emf tells us how much voltage the battery can ideally provide without any losses.
- Using our calculated internal resistance \( r = 0.36 \text{ ohms} \), the emf can be found by rearranging and solving the formula with given potential differences and currents.