Exploring Electromagnetism and Motors

Which of the following best describes the motor effect?

• The production of a magnetic field by a moving charge

• The force experienced by a current-carrying conductor in a magnetic field

• The generation of an electric current by a changing magnetic field

• The attraction between two stationary magnets

What is the direction of the force on a current-carrying conductor placed in a magnetic field determined by?

• left hand palm rule

• Righthand palm rule

• Lenz’s law

• Ohm’s law

In an electric motor, what is the primary function of the commutator?

• To increase the current

• To reverse the direction of current in the coil every half turn

• To generate a magnetic field

• To reduce friction

Which of the following is NOT an application of the motor effect?

• Loudspeakers

• Electric motors

• Transformers

• Galvanometers

What is electromagnetic induction?

• The process of generating a magnetic field by a current

• The process of generating an electric current by changing a magnetic field

• The process of attracting iron objects using a magnet

• The process of converting electrical energy to heat

Which law states that the induced current in a circuit will flow in such a direction as to oppose the change that produced it?

• Faraday’s law

• Lenz’s law

• Ohm’s law

• Ampère’s law

The magnitude of the induced electromotive force (emf) in a coil is proportional to:

• The resistance of the coil

• The rate of change of magnetic flux through the coil

• The length of the coil

• The temperature of the coil

Which of the following devices uses electromagnetic induction to generate electricity?

• Electric motor

• Generator

• Transformer

• Battery

In a simple DC motor, what causes the coil to continue rotating after it reaches the vertical position?

• The inertia of the coil and the action of the commutator

• The magnetic field alone

• The resistance of the coil

• The battery voltage