Definitions I Must Know

What is meant by a magnetic field?

A region in which a magnetic pole experiences a force

What is meant by the direction of a magnetic field?

The direction of the force on the N pole of a magnet at that point

What factors increase the emf induced in electromagnetic induction?

Move wire faster, stronger magnetic field, greater length of wire/ more turns on coil

What factors increase the rate of rotation of a motor?

Greater current, stronger magnetic field, more turns on the coil

What is the purpose of a split ring commutator in a motor?

To reverse the direction of current in the coil every half turn, allowing the motor to continue spinning in the same direction

What is meant by a step-up transformer?

A transformer with more turns on the secondary coil than the primary coil

Explain the principle of operation of a simple iron-cored transformer.

Alternating current in the primary coil produces an alternating magnetic field in the core, which channels the field to the secondary coil, inducing an alternating emf in the secondary coil

What are the advantages of high-voltage transmission?

High voltage transmission requires lower current for the same power, reducing energy lost in the resistance of the cables