Answer:

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


Convert km to m. -> 320km=320000 m
Convert hours to seconds -> 4 hrs=14400 s
Divide the distance by time because v=d/t
320000/14400=22.22 m/s
Im 70 percent sure that the right answer is chromosphere
1. Magnets attract iron and other ferromagnetic materials such as neodymium and cobalt.
2. Magnets attract or repel other magnets.
3. In addition one part of a magnet will always point north when allowed to swing freely.