Question

name:
ohms law practice problems
calculate the current in following circuits, show your work:
1.
2.
3.

Explanation:

Step1: Recall Ohm's Law

Ohm's Law is $I=\frac{V}{R}$, where $I$ is current, $V$ is voltage and $R$ is resistance.

Step2: Solve for circuit 1

First find total resistance $R_{total}=5 + 8+5=18\Omega$, and $V = 9V$. Then $I=\frac{V}{R_{total}}=\frac{9}{18}=0.5A$.

Step3: Solve for circuit 2

Total resistance $R_{total}=2.5 + 3=5.5\Omega$, and $V = 1.5V$. Then $I=\frac{V}{R_{total}}=\frac{1.5}{5.5}=\frac{3}{11}\approx0.27A$.

Step4: Solve for circuit 3

Total resistance $R_{total}=25+20 = 45\Omega$, and $V = 1.5V$. Then $I=\frac{V}{R_{total}}=\frac{1.5}{45}=\frac{1}{30}\approx0.033A$.

Answer:

1. $0.5A$
2. $\frac{3}{11}A\approx0.27A$
3. $\frac{1}{30}A\approx0.033A$