A battery has an emf of 12.0 V and an internal resistance of 3.00 Ω.If the battery delivers 120 mA when connected to a load,what is the load resistance?
A)97.0 Ω
B)100 Ω
C)4.00 Ω
D)36.0 Ω

Question

Quizplus · Accepted Answer

The load resistance can be calculated using Ohm's law and the formula for total voltage in a circuit, which includes both the emf (electromotive force) and the voltage drop across the internal resistance. The emf is given as 12.0 V, the internal resistance is 3.00 Ω, and the current is 120 mA (or 0.120 A). The voltage drop across the internal resistance is $I \times r = 0.120 A \times 3.00 Ω = 0.36 V$. Thus, the voltage across the load is $12.0 V - 0.36 V = 11.64 V$. The load resistance $R$ can then be found using $V = IR$, giving $R = \frac{V}{I} = \frac{11.64 V}{0.120 A} = 97.0 Ω$.

A Battery Has an Emf of 12