Question

IP A spark plug in a car has electrodes separated by a gap of 6.0x102 in. To create a spark and ignite the air-fuel mixture in the engine, an electric field of 2.5x10° V/m is required in the gap. 1. What potential difference must be applied to the spark plug to initiate a spark? (Answer in v 2. Find the potential difference for a separation of 0.12 in. (Answer in V)

Answer 1

1.Given the gap between the electrodes=6.0*10^-2 in=0.06in=0.001524m

The electric field required=2.5*10^6 V/m=2500000 V/m

From the given fields we have to find out the potential difference.For that we must consider the equation

E=V/d

where E is the electric field,V is the potential difference and d is the distance between the electrodes.

substitute the values in the above equation we get,

V=E*d=2500000*0.001524=3.81*10^3 V=3810V

2.Given the gap between the electrodes=0.12 in=0.003048m

The electric field is same as in the above question.

Now consider the equation,

E=v/d

substitute values in the above equation we get

V=E*d=2500000*0.003048=7.62*10^3 V=7620 V