20.1 Magnetic Fields, Field Lines, and Force
For a magnet, a domain refers to ______.
- the region between the poles of the magnet
- the space around the magnet that is affected by the magnetic field
- the region within the magnet in which the magnetic poles of individual atoms are aligned
- the region from which the magnetic material is mined
In the region just outside the south pole of a magnet, the magnetic field lines ______.
- point away from the south pole
- go around the south pole
- are less concentrated than at the north pole
- point toward the south pole
True or false—If a magnet shatters into many small pieces, all the pieces will have north and south poles
20.2 Motors, Generators, and Transformers
An electrical generator ________.
- is a generator powered by electricity
- must be turned by hand
- converts other sources of power into electrical power
- uses magnetism to create electrons
A step-up transformer increases the
- voltage from power lines for use in homes
- current from the power lines for use in homes
- current from the electrical generator for transmission along power lines
- voltage from the electrical power plant for transmission along power lines
What would be the effect on the torque of an electric motor of doubling the width of the current loop in the motor?
- Torque remains the same.
- Torque is doubled.
- Torque is quadrupled.
- Torque is halved.
20.3 Electromagnetic Induction
What does emf stand for?
- electromotive force
- electro motion force
- electromagnetic factor
- electronic magnetic factor
True or false—If you drop a bar magnet through a copper tube, it induces an electric current in the tube.