Question

Lightning is very good example of natural current. In typical lightning, there is 10⁹ J energy transfer across the potential difference of 5 x 10⁷ V during a time interval of 0.2 s.

Using this information, estimate the following quantities (a) total amount of charge transferred between cloud and ground (b) the current in the lightning bolt (c) the power delivered in 0.2 s.

Answer 1

During the lightning energy, E = 10⁹ J

Potential energy, V = 5 x 10⁷ V

Time interval, t = 0.2 s

(a) Amount of charge transferred between cloud and ground, 

q = It

(b) Current in the lighting bolt, E = VIt

I=100A

∴ q = It = 100 x 0.2

q = 20C.

(c) Power delivered, E = VIt

P = VI = 5 × 10⁷ × 100 = 500 × 10⁷

I = 5 × 10⁹ W

P = 5 GW.