Question

The storage battery of a car has an emf of $12V$. If the internal resistance of the battery is $0.4\Omega$, what is the maximum current that can be drawn from the battery?

Answer 1

Given,

Emf of the battery, $E=12V$
Internal resistance of the battery, $r=0.4\Omega$
Let the maximum current drawn from the battery be ${}^{\prime }{I}^{\prime }$
Then, according to Ohm's law,

$\Rightarrow I_{max}=\frac{E}{r}$
$\Rightarrow \frac{12}{0.4}=30A$

Therefore, the maximum current that can be drawn from the given battery is $30A$.