Basic Magnet Vocabulary
This is an area of force exerted by magnets on other magnets and objects made of magnetic material.
This is current that flows in only one direction through a wire.
What is a direct current?
This is a machine that changes electrical energy into mechanical energy.
What is an electric motor?
Contrast AC and DC.
Alternating current reverses direction in a regular pattern. Direct current flows in only one direction.
Alternating current is provided by an outlet (or generator). Direct current is provided by a battery.
Daily Double! A transformer increases the input voltage from 350 V to 1050 V. What is the ratio of the number of wire turns on the primary coil to the number of turns on the secondary coil?
1:3
1/3
0.33333
350/1050
These are the places on a magnet that exert the strongest magnetic force.
What are magnetic poles?
This is electric current that reverses the direction in a regular pattern.
What is alternating current?
This is a machine that uses electromagnetic induction to change mechanical energy into electrical energy.
What is a generator?
Compare and contrast a generator and electric motor.
Both use an electromagnet. Both produce energy.
A generator produces electric current, but a motor uses electric current.
A generator requires mechanical input, but a motor outputs mechanical energy.
A transformer decreases the input voltage from 81,000 V to 90 V. What is the ratio of the number of wire turns on the primary coil to the number of turns on the secondary coil?
900:1
This is a group of atoms with their magnetic poles lined up in the same direction.
What is a magnetic domain?
This is a single wire carrying electric current that is wrapped into a cylinder-shaped coil.
What is a solenoid?
This is a generator that has magnets connected to a large windmill-like wheel that rotates when pushed by steam, water, or wind.
What is a turbine.
Daily Double! Compare and contrast a permanent magnet and an electromagnet.
Both have a magnetic field.
Permanent magnets always have a magnetic field. Electromagnets are temporary magnets and only have a magnetic field when there is current supplied.
A step-down transformer reduces a 7700-V current to 7 V. If the primary coil has 11,000 turns of wire, how many turns of wire are there on the secondary coil?
10
This is a magnet whose domains remain aligned without an external magnetic field.
What is a permanent magnet?
This is a temporary magnet created when there is a current in a wire coil wrapped around an iron core.
What is an electromagnet?
This device is used to increase or decrease the voltage of an alternating current.
What is a transformer?
Compare and contrast a step up transformer and a step down transformer.
Both change the voltage of an alternating current.
Step up transformers increase voltage, step down transformers decrease voltage.
Step up transformers have more primary coils than secondary, step down transformers have more secondary coils than primary.
A step-up transformer increases a 14-V current to 168 V. If the secondary coil has 84 turns of wire, how many turns of wire are there on the primary coil?
7
This is the interaction between magnets and electric charges.
What is electromagnetism?
This is the making of current by a changing magnetic field.
What is electromagnetic induction?
Daily Double! This is a device that uses an electromagnet to measure electric current.
What is a galvanometer?
Compare and contrast a battery and electromagnetic induction.
Both provide current.
A battery provides current when a conductor is attached at both ends forming a closed loop for voltage difference to flow. Electromagnetic induction produces current by a changing magnetic field from wire loop(s) moving across a magnetic field.
A step-down transformer has 1400 turns of wire in its primary coil and 56 turns of wire in its secondary coil. If the output voltage is 9V, what is the input voltage?
225