Question

The gap between electrodes in a spark plug is 0.0006 m. Producing an electric spark in a gasoline-air mixture requires an electric field of 3.0x10^6 V/m. What minimum potential difference must be supplied by the ignition circuit to start a car?

Answer 1

In order to find the necessary potential difference to start the car, we can just multiply the electric field required by the gap between electrodes.

So we have:

`\begin{gathered} V=E\cdot d \\ V=3\cdot10^6\cdot0.0006 \\ V=1800 \end{gathered}`

So the necessary potential difference is 1800 V.