31 questions
This picture best illustrates the construction of a(n)
magnet
electromagnet
series circuit
parallel circuit
Which of the following is not a good conductor?
Copper
Silver
Aluminium
Plastic
a magnetic crane picks up pieces of metal in the picture. the crane magnet is made by electrified current and a coil. Most likely, what element is the metal?
copper
steel
aluminum
iron
These magnetic domains are:
strongly magnetized
slightly magnetized
unmagnetized
not enough information to tell
In a magnet, magnetic domains are:
all aligned
not aligned
some are aligned
there are no magnetic domains
How can the strength of an electromagnet be increased? (mark all that apply)
increase the current flowing through the coil
increase the number of coils
add an amplifier to it
put iron core inside the coil
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 strong electromagnet is used to attract pins.
What happens when the current in the coil is halved?
No pins are attracted.
Some pins are attracted, but not as many.
The same number of pins is attracted.
More pins are attracted.
Electric current is passing through a wire. Under which circumstances below will a magnetic field be created around the wire?
Only when the wire is absolutely straight.
Only when the wire makes a complete loop
Only when the current comes from a battery.
A magnetic field is always created around a wire when it carries electric current.
What produces ALL magnetic fields?
Moving charged particles.
Moving particles.
Charged particles at rest.
Moving particles of Earth.
Which diagram below best represents the magnetic field around a current carrying wire. The arrow represents the direction of the current.
There is no current.
Finish this sentence: "As the electric current through a wire INCREASES..."
The magnetic field around the wire becomes weaker
The magnetic field around the wire stays the same
The magnetic field around the wire becomes stronger
A wire loop is connected to only a light bulb. In order for the light bulb to turn on, what must happen?
The magnet must stay still
The circuit has to be open
The magnet must be moving
What would we change to reverse the north & south poles on an electromagnet?
direction of the current
number of coils
strength of the voltage
Which of the following is FALSE?
The current will not flow through a wire if the magnet is outside of the coil
The direction a coil of wire moves through a magnetic field determines the direction of the electric current
Current will flow through a wire as long as the magnetic field around the coil is changing.
Fill in the Blank: By changing the current in the wire, you can change the ___________ of an electromagnet.
strength and charge
direction and coils
strength and polarity (where North and South Poles are located)
Which is the best prediction for what will happen to the needle on the meter when the magnet stops moving and then is moved DOWN through the loop of the wire?
The reading will not change
The reading will drop to zero and then return to the same reading
The reading will drop to zero and then move in the opposite direction
In the figure shown, what happens when the amount of current flowing in the wire coil is increased?
The magnetic field becomes weaker
The position of the north and south poles is reversed
The magnetic field becomes stronger
In the figure shown, what happens when the direction of current flowing in the wire coil is reversed?
The magnetic field becomes weaker
The position of the north and south poles is reversed
The magnetic field becomes stronger
True or False: an electromagnet is a current carrying wire wrapped around a COPPER core
True
False
Select which of the following does NOT increase the strength of an electromagnet.
Increase the number of wire coils
Increase the amount of voltage
Increase the distance from the coils