19 Electromagnetic Induction

Why does the induced current flow in that direction/why does the speed of the magnetic object decrease

By faradays law of electromagnetic induction, the changing magnetic flux linkage induces an emf in the solenoid. Since the circuit is closed, the induced emf produces an induced current. By Lenzs law, the magnetic is repelled by the north pole induced on the top of the solenoid produced by the induced current.

What happens to the voltmeter reading when the switch is open

It deflects in the opposite direction. The magnetic flux linksge decreases. The induced EMF reversed in polarity to oppose this change in magnetic flux linkage.

How do you increase induced EMF

Use a stronger magnet or use a solenoid with more turns, increase the magnetic field, increase the speed of rotation, wind the coil around a soft iron rod.

How is an alternating current produced in the secondary coil.

The alternating input voltage produced an alternating magnetic field. The soft iron coild strengthens and directs the magnetic field produced by the primary coil towarfs the secondary coil. By Faradays law of electromagnetic induction, the changing magnetic flux linkage induces an alternating output voltage through the secondary coil. Since the circuit is closed, the alternating voltage produces an alternating current in the secondary coil.

Describe the EMF of an AC generator at Vpp

The plane of the coil is parallel to the magnetic field lines. Sides AD and BC cut the magnetic field lines at the greatest rate. The magnitude of the induced EMF is the largest. The maximum induced current flows.

Describe the EMF of an AC generator when current is 0.

The plan of the coil is perpendicular to the magnetic field lines. Sided AD and BC of the coil move parallel to the magnetic field lines and do not cut them. The induced emf is zero. The induced current is zero.