Science Chapters 10 & 11

Electricity and Magnetism

What does the magnetic field protect us from?

Solar wind (ionized particles from the sun)

How is static electricity different than current electricity?

Static charges are mostly stationary.

What is the Law of Charges?

Law of Charges - like charges repel, unlike charges attract

What is the Law of Magnetism?

Opposite magnetic poles attract; like magnetic poles repel

What type of charges do electrons have?

Negative

What type of particle has a positive electrical charge?

Proton

What is electrical affinity?

An object’s ability to attract electrons.

What conditions must be met for two objects to create a static charge?

If two objects with different electrical affinities rub against each other, one will steal electrons from the other, causing both objects to have static electricity

What is the SI unit for electrical charge?

Coulomb

How many particles are in 1 C of positive charge?

6\.24 X 10^18 protons

In the electrical induction simulation, why was the balloon able to pull electrons off of the sweater?

Electrical affinity

Explain why bringing the charged balloon near the neutral wall was able to shift charges around and the balloon was able to stick to the wall

The charged balloon is negative, and negatives repel other negatives, so the balloon pushes the negative charges on the wall away. There is then a local difference between the negatives on the balloon and the positives on the wall, so the balloon is attracted to the wall and is able to stick.

Why is water affected by static electricity?

Because it is naturally polar

What device uses statically charged plates to clean dirty air in smoke stacks and even household air purifiers?

Electrostatic precipitators

What device stores static electricity for a quick discharge, such as for a camera flash or a taser?

Capacitor

What extreme form of static electricity did Benjamin Franklin supposedly use a kite and a key to investigate?

Lightning

What is the usual source of electricity in a DC circuit?

A battery

What is anything that is powered by an electrical circuit?

Electrical load

Potential electrical difference

Voltage

Amount of charge

Coulomb

Resistance

Ohms

Current

Amps

kWh

Energy

Watt

Power

Limited by circuit breakers

Amps

 A typical flashlight bulb has a resistance of 60. Ω. If the bulb is used in a flashlight that uses 4 "D" cell batteries, how much current does it draw? Be sure to include units

.10 Amps

What do GFI’s measure?

If there is an imbalance between current going in and the current going out

WHY are GFIs installed, that is, what do they prevent?

They prevent faulty equipment from short circuiting or electrocuting someone

What happens to the north and south poles of a magnet when you cut a magnet in half?

The two halves will still have a north and south pole

How fast has earth's magnetic north pole been moving?

40 kilometers per year

 What is the term for the difference between magnetic north and true north?

Magnetic declination

Magnets allowed to freely hang from a string will point their north end toward earth's north pole. What pole of the magnet must exist at earth's north pole?

South

 What type of electricity creates a magnetic field?

Flowing electricity

What is the "right hand rule" for electromagnetism?

If you grasp a wire so that your right thumb points in the direction of the flow of the convectional current, the magnetic lines of force caused by the current will point in the direction your fingers wrap around the wire.

How do we generate AC electricity?

Turning a magnet near a loop of wire

How does an electroscope work?

When something that has a static charge on it is brought near the electroscope, it charges the top of the electroscope by electrical induction This causes the top of the electroscope to have the opposite charge Because both leaves of the foil inside the electroscope have the same charge as each other, they repel each other.

Under what condition would an object have static electricity?

If it has an unequal number of electrons and protons

What equation relates voltage, current, and resistance?

Ohm’s Law

What is a loop of wire that contains flowing electricity with an iron core in its center?

Electromagnet

What type of field can move an ion?

Magnetic

In reality, what moves along a wire during AC electricity?

Electrons, not protons

How do capacitors work?

Capacitors use static electricity for quick discharge, such as a camera’s flash bulb or a taser.

Who came up with the convention of positive charges moving?

Benjamin Franklin

How do laser printers work?

Laser printers put charges onto a roller and use that to guide toner onto a page