A two-branch parallel circuit has a 30 Ω and a 15 Ω resistor. What is the total resistance?
A) 2 Ω
B) 10 Ω
C) 45 Ω
D) 15 Ω

Question

Quizplus · Accepted Answer

The total resistance $R_{total}$ in a parallel circuit is given by $\frac{1}{R_{total}} = \frac{1}{R_1} + \frac{1}{R_2}$. For a 30 Ω and a 15 Ω resistor in parallel, $\frac{1}{R_{total}} = \frac{1}{30} + \frac{1}{15} = \frac{1}{30} + \frac{2}{30} = \frac{3}{30}$, so $R_{total} = \frac{30}{3} = 10 \Omega$.

A Two-Branch Parallel Circuit Has a 30 Ω and a 15