Question

An automobile starter motor is connected to a 12.0 V battery.
When the starter is activated it draws 150 A of current,
and the battery voltage drops to 7.0 V. What is the battery’s
internal resistance?

Answer 1

@robtobey

Answer 2

The voltage drop across the internal resistance is 12 - 7 = 5 volts.
Internal resistance is given by:
\[\Large R _{internal}=\frac{V}{I}=\frac{5}{150}=(you\ can\ calculate)\ \Omega\]