Question

A spark is generated in an automobile spark plug when there is an electric potential of 3000 V across the electrode gap. If 60 W of power is generated in a single spark that delivers a total charge of 3 nC, how long does it take for the spark to travel across the gap?

A. 50 ns
B. 75 ns
C. 125 ns
D. 150 ns
E. 225 ns 5

Answer 1

The correct option is d

Step-by-step explanation:

From the question we are told that

The electric potential is
`V = 3000 \ V`

The power is
`P = 60 \ W`

The charge delivered is
`q = 3nC = 3.0 *10^(-9) \ C`

Generally the power generated is mathematically represented as

`P = I V`

=>
`I = (P)/(V )`

=>
`I = (60 )/(3000 )`

=>
`I = 0.02 \ A`

This current flow is mathematically represented as

`I = (q -q_o)/(\Delta t )`

Where
`q_o` is the charge delivered at t=0 s which is 0s

So

`0.02 = ( (3.0 *10^(-9)) -0 )/(t - 0 )`

`t = 1.50 *10^(-7 ) \ s`

`t = 150 *10^(-9 ) \ s`