David Sang and Graham Jones Solutions for Chapter: Practical Circuits, Exercise 3: Questions

A car battery has an e.m.f. of $12 \mathrm{V}$ and an internal resistance of $0.04\Omega$. The starter motor draws a current of $100 \mathrm{A}$.

Calculate the terminal p.d. of the battery when the starter motor is in operation.

A car battery has an e.m.f. of $12 \mathrm{V}$ and an internal resistance of $0.04\Omega$. The starter motor draws a current of $100 \mathrm{A}$.

(b) Each head lamp is rated as $\text{'}12\mathrm{V},36\mathrm{W}\text{'}$. Calculate the resistance of a headlamp.

A car battery has an e.m.f. of $12 \mathrm{V}$ and an internal resistance of $0.04\Omega$. The starter motor draws a current of $100 \mathrm{A}$.

(c) To what value will the power output of each headlamp decrease when the starter motor is in operation? (Assume that the resistance of the headlamp remains constant.)