Question

The magnetic field at the earth's surface can vary in response to solar activity. During one intense solar storm, the vertical component of the magnetic field changed by 2.8 μT per minute, causing voltage spikes in large loops of the power grid that knocked out power in parts of Canada

What emf is induced in a square 170 km on a side by this rate of change of field?

Express your answer with the appropriate units.

Answer 1

Emf induced e   = rate of change in Magnetic flux

             e = d(BA)/dt

        e = A dB/dt

         = (170 x 10^3)^2 m^2 * ( 2.8 x 10^-6 T / 60 sec ) = 1348.67 Volt