A 10-ohm resistor is attached to a 20-ohm resistor in series.This combination is then attached to a 30-ohm resistor in parallel.This is then connected to a 120-V battery.What is the current flow through the 20-ohm resistor?
A)4.0 A
B)6.0 A
C)8.0 A
D)16 A
E)18 A

Question

Quizplus · Accepted Answer

First, calculate the total resistance of the circuit. The 10-ohm and 20-ohm resistors in series have a combined resistance of 30 ohms. This is in parallel with another 30-ohm resistor, so the total resistance of the parallel combination is 15 ohms (using the formula for parallel resistors: 1/R_total = 1/R1 + 1/R2, which gives R_total = (R1*R2) / (R1+R2) = (30*30) / (30+30) = 900/60 = 15 ohms). The current from the battery is then I = V/R = 120V / 15 ohms = 8A. Since the 10-ohm and 20-ohm resistors are in series, they have the same current flowing through them, which is the total current of 8A.

A 10-Ohm Resistor Is Attached to a 20-Ohm Resistor in Series.This