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?

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

now we have

here since magnetic field is constant so we have

now we have

now we have

the cellphone, they would then know if the killer would have contacted them or always hated them. or if it was a breakup. but if that is not the case, then it would be the clothing. to put in a bullet, it would have to be put in by hands. hands have finger prints which, would have giving you the answer of who done it.

explanation: