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 190km on a side by this rate of change of field?

Answer 1

Answer:

$EMF = 1684.67 Volts$

Explanation:

As we know that EMF is induced in a closed conducting loop if the flux linked with the loop is changing with time

So we can say

$EMF = \frac{d\phi}{dt}$

now we have

$\phi = BA$

here since magnetic field is constant so we have

$EMF = A\frac{dB}{dt}$

now we have

$A = (190 \times 10^3)(190 \times 10^3)$

$A = 3.61 \times 10^{10} m^2$

now we have

$EMF = 3.61\times 10^{10} (\frac{2.8 \times 10^{-6}T}{60 s})$

$EMF = 1684.67 Volts$