13.1 Electromagnetic Induction

Question 1

electromagnetic induction

Answer 1

the production of electric current in a conductor moving through a magnetic field

Question 2

law of electromagnetic induction

Answer 2

a change in the magnetic field in the
region of a conductor induces a voltage in
the conductor, causing an induced electric
current in the conductor

Question 3

how does a coiled conductor affect electromagnetic induction

Answer 3

by coiling a conductor you can create a magnetic
field similar to that of a bar magnet

the magnetic fields from both sides of the loop interact to produce a more pronounced magnetic field in the centre of the loop.

similarly, with electromagnetic induction, a coiled conductor has more induced electric current in it than does a straight conductor.

Question 4

how does the number of loops in the coil affect electromagnetic induction

Answer 4

increasing the number of loops in a coiled conductor, or solenoid, produces a stronger magnetic field for a given electric current

with electromagnetic induction, the number of loops in the coil is directly proportional to the magnitude of the electric current induced in the conductor for a given change in the magnetic field

so, the greater the number of loops in a coil, the more electric current can be induced for a given change in the magnetic field

Question 5

how does the rate of change of the magnetic field affect electromagnetic induction

Answer 5

There are two cases to consider here: a coiled conductor with a permanent magnet
and a Faraday’s ring apparatus.

In the case of a coiled conductor with a permanent
magnet, the more quickly you move the magnet into, or out of, the coil, the greater is the rate of change you cause in the magnetic field within the coil.

A higher rate of change causes a larger induced electric current in the conductor.

In the second case of Faraday’s ring, the more quickly you increase the current in the primary circuit, the greater is the rate of change you cause in the magnetic field in the coiled conductor and the soft-iron ring.

The magnitude of the induced electric current in the secondary circuit is proportional to the rate of change of the magnetic field in the soft-iron ring.

Question 6

how does the strength of the inducing magnetic field affect electromagnetic induction

Answer 6

The stronger the inducing magnetic field, the greater is the induced electric current.

So, a stronger permanent magnet induces a greater electric current in a given coil.

Similarly, in a Faraday’s ring, a greater electric current in the primary circuit increases the strength of the magnetic field in the coiled conductor and soft-iron ring.

This increases the induced electric current in the secondary circuit.