Exam 7: Magnetism and Electromagnetism

The principal difference between a solenoid and a relay is that:

The quantity of lines of force per unit of area is known as ________.

An iron core electromagnet has a higher ________ than an air core electromagnet.

A permanent magnet will retain its magnetism for a long period of time.

A strong magnetic field around a conductor indicates a small current flowing through the conductor.

The voltage produced by a magnetic field cutting through a conductor depends on the ________.

An ampere-turn is a unit of ________.

Electromagnetic induction is best defined as the process by Which a voltage is produced in a conductor When there is:

The left-hand rule can be used to determine the amount of magnetomotive force.

The ________ electromagnet cannot be further magnetized.

If more turns of Wire are added to a coil and then that coil is moved through a magnetic field, the voltage produced Will ________.

The amount of voltage that is induced in a conductor depends on the ________.

Reversing the current through an electromagnet ________ the magnetic field.

How does the magnetic field change around a conducting wire if the current increases?

A simple electric doorbell probably uses ________ to ring the bell.

If a higher voltage is needed from a generator,What must be done?

Permeability is ________.

If a tape recorderʹs output voltage increases and decreases when you shake the recorder, a possible problem might be ________.

The purpose of a commutator in a dc generator is to:

According to the left-hand rule for the magnetic field around a conductor,W hat points in the direction of current flow?