Acoil of insulated wire is wound many times around an iron bar. the wire is connected to a battery and a contact switch. the contact switch is alternately flipped closed and left closed, so the wire carries a current through it, and then flipped open and left open, so that the current stops. describe what magnetic fields are created, if those magnetic fields in turn induce an emf, and whether the induced emf is in the direction of the original current or opposite
to it. justify your answer using lenz's law and the conditions which can cause a magnetic field to induce an emf. you may draw a diagram if it you to visualize the apparatus.

As per faraday's law the rate of change in magnetic flux linked with a coil will induce EMF in the coil. It is given by

now here as we are closing the switch and then open it alternatively so it will change the value of current in the coil.

This change in current will change the magnetic flux in the coil due to which it will induce EMF in it.

Now by Lenz the the direction of induce current in the coil will always opposite to the causes due to which it is induced.

As we know that when switch is connected to flow the current the direction of induced current is in opposite to the current so that it will oppose the increasing value of current while when we open the switch the induced current is in direction of the current so that it will increase the value of decreasing current in the loop.

answer: b.

explanation: