Chapter 16 Test Flashcards
Who suggested the earth was a big magnet?
William Gilbert
Three properties of magnets
Has 2 poles, exert forces on each other, surrounded by magnetic field
As electrons move, what do they create?
Electric current and charges
Electric current is made when something happens to a magnetic field. What happens?
Change happens
Explain why rotating either the coil or the magnet induces an electric current
It changes the magnetic field
List 3 things that can happen to a magnet that will de magnetize
Dropping it, heating it, or putting it by an opposite force too strong
What are the two main types that we discussed?
Electromagnetic & Ferromagnetic
Temporary & perminate
What are two effects of the earth’s magnetic field?
Auroras
North and south poles
What can you make visible by sprinkling iron filings around a magnet?
A magnetic field
What did Faraday’s experiments with magnets and electromagnetic induction demonstrate?
Electric current is made when magnetic fields change
What do we call a coil of wire with an electric current?
A solenoid
What do we call a device that increases the voltage of an alternating current?
A step up transformer
What do we call electric current changing directions?
Alternating current
what do you end up with if you cut a magnet in half?
Two smaller magnets that have both polls.
What does a step down transformer do the voltage and current?
It decreases the voltage
What does a step up transformer do the voltage and current?
It increases the voltage
What does an electric current produce?
Magnetic field
What geographic pole does the marked end of a compass point to?
North
What happens to the magnetic field of the solenoid when you increase the number of loops per meter?
It gets stronger
What is created when a magnet moves through a coil of wire?
Electromagnet
What is created when a wire moves between the poles of a magnet?
An electric current
What to things strengthen a magnetic field made by a current carrying wire?
More loops, more batteries, and an iron core.
What two things can you do to strengthen the power of an electromagnet
More batteries and more loops.
What is an object magnetic?
When the domains are aligned and made out of iron nickel or cobalt
Whether a material is magnetic or not depends on what?
The domains and the material
Why are auroras usually seen only in areas near the poles rather than areas near the equator?
Because the strongest magnetic field is near the poles
Why does the compass needle respond to a magnetic field?
Because it is a magnet
Why would our moon not have auoras?
Because it doesn’t have an atmosphere or magnetic field?
