Question

An unusual lightning strike has a vertical portion with a current of −400 A downwards. The Earth's magnetic field at that location is parallel to the ground and has a magnitude of 30 μT. Calculate, in N, the force exerted by the Earth's magnetic field on the 25-m-long current.

Answer 1

0.3 N

Step-by-step explanation:

i = 400 A

B = 30 x 10^-6 T

L = 25 m

Force due the current carrying conductor placed in a magnetic field

F = B i L SinФ

where, Ф be the angle between length vector and magnetic field vector

F = 30 x 10^-6 x 400 x 25 = 0.3 N