A spark plug in a bike or a car is used to ignite the air - fuel mixture in the engine. It consists of two electrodes separated by a gap of around 0.6 mm gap as shown in the figure.

To create the spark an electric field of magnitude `3xx10^(6)Vm^(-1)` is required. (a) What potential difference must be applied to produce the spark ? ( b) If the gap is increased , does the potential defference increase decrease or remains the same the same ? ( c) find the potential difference if the gap is 1 mm .

Explanation

Electric field `E = 3 xx 10^6 Vm^-1`
Distance of separation
d = 0.6 mm = `0.6 xx 10^-3m`
`E = V/d`
(a) `:.` Potential difference to be applied
V = E `xx` d
V = `3 xx 10^6 xx 0.6 xx 10^-3`
`= 1.8 xx 10^3 = `1800V
(b) If the gap is increased (d is increased) then potential difference
V = E `xx` d
`:.` Potential difference would be increased.
(c) If `d = 1 xx 10^-3` m and `E = 3 xx 10^6Vm^-1`
Then potential difference
V = E `xx` d
`V = 3 xx 10^6 xx 10^-3 = 3 xx 10^3`
= 3000 V