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

Answer:

The correct option is  d

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

         $P = I V$

=>      $I = \frac{P}{V }$

=>       $I = \frac{60 }{3000 }$

=>     $I = 0.02 \ A$

This  current flow is mathematically represented as

           $I = \frac{q -q_o}{\Delta t }$

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

     So

             $0.02 = \frac{ (3.0 *10^{-9}) -0 }{t - 0 }$

               $t = 1.50 *10^{-7 } \ s$

               $t = 150 *10^{-9 } \ s$