Question

A car battery with a potential difference of 11.4 volts is connected to a starter motor with a resistance of 0.242 ohms. If the startup time is 1.54 seconds, how many electrons flow out of the battery during this time? Answer must be in 3 significant digits.

Answer 1

Given

The potential difference is V=11.4 V

Resistance is R=0.242 ohm

Time taken, t=1.54 sec

To find

The number of electron flow.

Explanation

Let the number of electron be n

We know current is charge per unit time

Thus,

$I=\frac{q}{t}=\frac{ne}{t}$

By Ohm's law,

$\begin{gathered} V=RI \\ \Rightarrow V=\frac{Rne}{t} \\ \Rightarrow11.4=\frac{0.242\times n\times1.6\times10^{-19}}{1.54} \\ \Rightarrow n=4.53\times10^{20} \end{gathered}$

Conclusion

The number of electron flow is

$4.53\times10^{20}$