All atoms are like tiny magnets. Why do only a few materials show magnetic properties?
Magnetic properties are displayed when the atoms in a substance LINE UP in the same direction throughout the material in a magnetic domain.
Where is the Earth’s magnetic north pole?
At the Earth’s geographic south pole (Antarctica)
What type of magnet is create by an electric current?
The device that switches the polarity of the magnets used in an electric motor is called a ____________?
A turbine is a? A. Motor B. Generator C. Electromagnet D. Compass
What country produced the first compass and uses its to help with navigation in shipping ?
If you reverse the direction of current flow in an electromagnet, what happens?
The north and south poles of the magnet are reversed.
Which of the following does not create a magnetic field? A. A lodestone B. A straight wire carrying current C. A coil of wire carrying current D. A metal ball with 2 coulombs of static charge on it.
D. A metal ball with 2 coulombs of static charge on it.
What do positive charges cause other positive charges and negative charges to do? (two parts)
Positive charges are repelled and negative charges are attracted.
An electric _______________ converts electric energy into mechanical energy.
An electric _______________ converts mechanical energy into electric energy.
Calculate the total resistance in the circuit.
This series circuit has 9 ohms of resistance. (3 ohms + 3 ohms + 3 ohms)
___________ _________ occurs when current is induced in a wire by a moving magnet.
A model of the forces exerted by a magnet is called a magnetic __________.
What does the magnetic forces do when two magnets with the same polarity come close together?
They repel each other
A commutator __________ the electromagnets from north to south at the right place to keep the rotor in an electric motor spinning.
What property of matter gives rise to both electricity and magnetism?
An electromagnet attracts and repels the magnets on a rotor by switching its polarity, this causes what to spin
The mathematical relationship between current, voltage & resistance is known as?
Mechanical energy is a form of kinetic energy and is the energy of _________.
Energy of movement or motion
What do we purchase from the power company? A. Power B. Voltage C. Current D. Energy
Four alkaline AA batteries places in series gives a total voltage of?
The magnetic force exerted by an electromagnet depends on three factors, 1. the amount of electric current, 2. the amount of iron in the core and 3.______ ?
the number of turns of the wire around the core.
An electric motor must have three things: 1.________ 2. stationary magnets the surround the rotating element and 3. the commutator.
A rotating element or rotor.
Electromagnetic induction creates what type of electric current?