Question

g A circular loop of wire with radius 3 m is flat on the xy plane in a magnetic field which is pointed in the z-direction and has a magnitude of 5 μT. What is the magnitude of the induced emf in the loop if the loop shrinks to a radius of 1.5 m in 3 seconds?

Answer 1

emf=-0.035V

Step-by-step explanation:

this problem can be solved with the Lenz's law:

`emf=-(\Delta \Phi_(B))/(\Delta t)`

where PhiB is the magnetic flux. In this case we have

`\Delta \Phi_(B)=B(A_1-A_2)`

due to the magnetic field is constant. A is the area of the circular loop. Hence

`\Delta \Phi_(B)=(5*10^(-3)T)(\pi(3m)^2-\pi(1.5m)^2)=0.106Tm^2`

Finally

`emf=-(0.106Tm^2)/(3s)=-0.035V`

HOPE THIS HELPS!!