Question

A lightning flash may transfer up to 14 C of charge through a potential difference of 107 V

How much energy does this involve?
For how long in minutes does this energy light a 100 W bulb?

Answer 1

Energy involved = 1498 J

Time taken by this energy to light a 100 W bulb = 0·25 min

Step-by-step explanation:

Charge that is transferred = 14 C

Potential difference = 107 V

Formula for power in terms of potential difference (V) and current (I) = V × I

And power is also equal to (work done) ÷ (time taken)

Current (I) = (charge transferred) ÷ (time taken)

Formula for energy = V × Q

where V is the potential difference

Q is the charge transferred

∴ Energy involved = 107 × 14 = 1498 J

Given power of the bulb = 100 W

Energy ÷ (time taken) = 100

1498 ÷ (time taken) = 100

∴ Time taken = 14·98 s = 14·98 ÷ 60 min = 0·25 min