If two magnets push each other away, what can you conclude about their poles?
The poles of the magnets are identical.
100
What is electromagnetism?
The interaction between electricity and magnetism
100
What is a generator?
A device that converts mechanical energy into electrical energy
100
Which powerline would most likely have the highest voltage?
A. The one supplying a residential area
B. The one near a power distribution center
C. The one near a power plant
D. The one along a highway
C. The one near a power plant
100
What metal is used to make ferromagnets?
Iron
Cobalt
Nickel
200
What is a magnet?
A magnet is any material that attracts iron or things made of iron.
200
What does a galvanometer measure?
electric current
200
What does a transformer do>
A transformer increases or decreases the voltage of alternating current
200
Electric outlets in the United States provide 120 volts of alternating current, while those in England provide 230 volts. What device is needed to run an American hair dryer in a British hotel?
Step-down Transformer
200
The marked end of a compass needle alwasy points directly to
A magnet's south pole
300
Which element has atoms whose magnetic fields do not cancel each other out?
Iron
300
What happens to the magnetic field of an electromagnet if you increase the current in the wire?
The magnetic field gets stronger
300
Describe the difference in a step-up transformer and a step-down transformer.
A Step-up transformer has fewer loops in its primary coil than in its secondary coil and increases the voltage of AC. A Step-down transformer has more loops in its primary coil than its secondary coil and decreases the voltage of AC.
300
Explain why some pieces of iron are more magnetic than others are.
Some pieces of iron are more magnetic than others because the domains of the magnetic pieces are more aligned. The domains of the less magnetic pieces are randomly arranged.
300
What do you end up with if you cut a magnet in half?
Two pieces each with a north pole and a south pole.
400
List two ways a magnet can lose its magnetic properties.
A magnet can lose its magnetic properties if it is:
dropped
hit
placed in a strong magnetic field that is opposite to its own
heated
400
Describe what happens when you hold a copass close to a waire carrying a current.
The needle may deflect and not point north.
400
What are three sources of energy that are used to generate electrical energy?
A nuclear reaction
Fossil Fuels
Wind
400
How could engineers remodeling a hydroelectric plant increase power output from the plant without replacing its magnet?
increase the height of the dam so that water will flow faster.
400
A junkyard electromagnet is strong enough to pick up cars, but not trucks. How could it be upgraded to lift larger vehicles?
The electric current and the number of coils in the solenoid could be increased.
500
What do scientists think causes Earth's magnetic field?
Scientists think that Earth's magnetic field is caused by the movement of electric charges in Earth's liquid outer core.
500
Compare the structures and magnetic fields of solenoids with those of electromagnets
A solenoid is a coil of wire that carries electric current. An electromagnet is a solenoid that has an iron core. An electromagnet has a stronger magnetic field than the solenoid has.
500
What did Faraday try to do in his experiment?
Faraday was trying to induce a current in a wire by using the magnetic field of an electromagnet.
500
Compare the function of an eletric generator with the function of an electric motor.
The function of a generator is opposite of the function of an electric motor. A generator converts mechanical energy into electrical energy and an electric motor converts electrical energy into mechanical energy.
500
John created a device to power his television made out of stationary bike, a thick rubber band, a magnet, a coil, and wire.
Which form of energy was converted to electrical energy?