16 questions
A magnetic field is a force field created by
gravity
force
magnets
Arrows are close together on a force field when the force is
stronger
weaker
opposite
A compass needle shows us the magnetic field of
the sun
Earth
the moon
a magnet that is near by
Earth has a magnetic field that is similar to a bar magnet's magnetic field.
true
false
Earth's magnetic South Pole is near Earth's geographic North Pole
true
false
Electronic devices create magnetic fields because they
are magnets
are compasses
have moving particles with electric charge
A compass needle points north because of Earth's magnetic field unless
it is close to a wire with a current
it is close to any wire
it is close to a battery
How can you test to see if there is a current running through a wire?
listen carefully to see if you hear a buzzing sound
place several compasses around the wire
place several batteries around the wire
The compass needles are turned by magnetic forces caused by electric current. The magnetic forces caused by an electric current are one kind of
gravitational force
gravitational field
electromagnetic force
The electromagnetic forces from a current carrying wire are strong enough to move the compass needle. The forces can be made stronger by
making the wire shorter
making the wire longer
making the wire into loops
An electromagnet is a magnet that
its strength can be varied and turned on and off
always has a magnetic field around it
has very little strength
Refrigerator magnets and bar magnets are what type of magnet?
electromagnet
electronic
permanent
What THREE ways are electromagnets different from permanent magnets?
they can be turned off and on
they can increase in strength by increasing the current in the wire
they are smaller in size
they can change which is the north and south pole
Electromagnets are useful in industry such as a junk yard because they
have strong north and south poles
are easy to lift
can be turned off and on
Permanent Magnets and Electromagnets are similar in which TWO ways?
it can be turned off and on
they both have a north and south pole
they are surrounded by a magnetic field
A force that can act at a distance is called
non contact force
friction
balanced