Question

a cell phone uses a 3.0 v battery. the circuit board it uses needs a 0.05 a current. what size resistor is needed to generate this current?

Explanation:

Step1: Recall Ohm's law

Ohm's law is $V = IR$, where $V$ is voltage, $I$ is current, and $R$ is resistance. We need to solve for $R$.

Step2: Rearrange the formula

Rearranging $V = IR$ for $R$ gives $R=\frac{V}{I}$.

Step3: Substitute values

Given $V = 3.0\ V$ and $I=0.05\ A$, we substitute into the formula: $R=\frac{3.0}{0.05}$.

Step4: Calculate the result

$R = 60\ \Omega$.

Answer:

60