What is the effective resistance of a car’s starter motor when \({\bf{150}}\;{\bf{A}}\) flows through it as the car battery applies \({\bf{11}}{\bf{.0}}\;{\bf{V}}\) to the motor?

The given data can be listed below as,

• The value of current flow is,\(I = 150\;{\rm{A}}\).
• The potential difference of the battery is, \(V = 11.0\;{\rm{V}}\).

According to Ohm's law, the value of potential difference across a specific electrical circuit is directly proportional to the electrical current flow. The proportionality constant in this relationship is the circuit element's resistance.

The expression to calculate the effective resistance of the car’s starter motoris expressed as,

\(\begin{align}V = IR\\R = \frac{V}{I}\end{align}\)

Here,\(R\)is the effective resistance of the car’s starter motor.

Substitute all the known values in the above equation.

\(\begin{align}R = \left( {\frac{{11.0\;{\rm{V}}}}{{150\;{\rm{A}}}}} \right)\\ \approx 0.0733\;{\rm{V/A}}\\ \approx \left( {0.0733\;{\rm{V/A}}} \right)\left( {\frac{{1\;{\rm{\Omega }}}}{{1\;{\rm{V/A}}}}} \right)\\ \approx 0.073\;{\rm{\Omega }}\end{align}\)

Thus, the effective resistance of the car’s starter motor is \(0.073\;{\rm{\Omega }}\).