Physics, Electricity and

Magnetism Vocabulary

Where do Polar Bears live?

The North Pole

What is polarity?

Electrical polarity (positive and negative) is present in every electrical circuit.

A magnet has a polarity, in that one end is the "north" and the other is the "south". Opposite poles attract but similar poles repell each other. You cannot make the north poles of two

magnets stick together.

What is the largest magnet?

• The following

What is a magnet?

a piece of iron (or an ore, alloy, or other material) that has its component

atoms(electrons) so ordered that the material

exhibits properties of magnetism

What is magnetism?

a physical phenomenon produced by the motion of electric charge, resulting in

attractive and repulsive forces between objects.

What happens when I hit the cue ball into the line of pool balls?

The end ball moves the others move a little.

What is electric current?

current is what happens when the random exchange of electrons that occurs constantly

in a conductor becomes organized and begins to move in the same direction.

even though the individual electrons move slowly, the current itself moves at nearly the

speed of light. Thus, when you flip a light switch, the light turns on immediately, no matter how much distance separates the

light switch from the light.

How is electricity measured?We know that electricity can be measured in volts. Household electricity is 120 volts (abbreviated 120 V). Flashlight batteries are 1.5 volts. Car batteries

are 12 volts.We also know that electricity can be measured in watts. Incandescent light bulbs are typically 60, 75,

or 100 watts. Compact fluorescent lights (CFLs) have somewhat smaller wattage ratings. Microwave

ovens and hair dryers are 1,000 or 1,200 watts.We also may know that there's a third way to measure

electricity, called amps. A typical household electrical outlet is 15 amps (abbreviated 15 A).

What is Kilowatt Hours

unit of energy equal to 1,000 watt-hours. The

kilowatt-hour is commonly used as a billing unit for

energy delivered to consumers by electric

utilities.

How do you calculate?Watts = Amps x Volts

Watts is also known as volt-amps and is typically used in conjunction with AC power circuits. Fill in any of the two

fields to find the value of the third.Example 1

You have a 12 Volt power supply that delivers 1 Amp of current. Fill in the Volts and Amps fields to find the Watts.

Example 2The AC24-40 power supply is a 24V AC power supply that can

power up to 40 VA.Enter 24 under voltsEnter 40 under watts

Click calculateYou get 1.66 in this example.

Thus, the AC24-40 can supply up to 1.6 Amps at 24V AC.

What is Conventional Current?In solid metals such as wires, the positive charge carriers are immobile, and only the

negatively charged electrons flow. Because the electron carries negative

charge, the electron motion in a metal is in the direction opposite to that of

conventional (or electric) current. from the positive terminal of a cell to its negative

terminal.

It is opposite in direction to the flow of electrons.

What is Electrical Potential energy?Potential energy is a form of

stored energyElectric Potential Energy is experienced by charges both different and alike, as they repel or attract each other.

What is Ohm’s law

This law defines the relationships between current, voltage and resistance.

A good way to understand ohms laws is an analogy with a domestic water system.

The same way that an electric current flows through a copper wire, water flows through a copper pipe in a water system. Most people do not think to much about the fact but when

they turn on tap the water comes out as a result of the pressure that is provided  by a pumping station some miles

away. This water pressure is similar to that used to drive electricity

around a circuit, the potential difference or pd for short is the term that is used - this is measured in volts.

This driving force is provided by a battery or in the case of mains electricity a generator at the power station

What is a Equivalent Resistance

how to connect individual resistors together to form either a Series Resistor Network or a Parallel Resistor Network and we used Ohms Law to find the

currents and voltages flowing in each resistor combination and

add them.

What is an Electric Field?Electric field is defined as the electric force per unit charge.

The direction of the field is taken to be the direction of the

force it would exert on a positive test charge. The electric field is radially outward from a positive charge and radially in

toward a negative point charge.

Electric Field Pictures.

What is a schmatic. a representation of the elements of a system using abstract, graphic symbols rather than realistic pictures..

Coulomb’s law

Coulomb's law describes the relationship between force, charge and distance. The law

looks at the forces created between two charged objects. As distance increases, the

forces and electric fields decrease.

What is Ohm’s law

V=I(R)V is Volts

I is Electric CurrentR is resistance(light bulb)

Plasma is?Plasma is a form (also called state) of matter. The three

other common states of matter are solids, liquids and gases, so plasma is sometimes called the fourth state of matter. Plasma is created by adding energy to a gas so its atoms and molecules separate (called ionization

) into negatively charged electrons, and positively charged ions. Unlike the other states of matter, the charged particles in a plasma will react strongly to electric and magnetic fields (i.e. electromagnetic

fields). If a plasma loses heat, the ions will re-form into a gas. Neon or Flourescent lights.

SuperpositionSuperposition and interference

When two electromagnetic waves of the same frequency superpose in space, the resultant electric and magnetic field strength of any point of

space and time is the sum of the respective fields of the two waves. When one forms the sum, both the magnitude and the direction of the fields need be considered, which means that they sum like vectors. In the special case when two equally strong waves have their fields in the

same direction in space and time (i.e., when they are in phase), the resultant field is twice that of each individual wave. The resultant intensity, being proportional to the square of the field strength, is therefore not two but four times the intensity of each of the two

superposing waves. Constructive or Destructive Interference.

Electric Generator

device that converts mechanical energy to electrical energy. (the opposite of an electric motor)

In the case of a home generator you are converting gasoline or natural gas into electricity

Turbine

Type of generator: turbine steam engine, water falling through a

turbine or waterwheel, a wind turbine,[

Induction isis the production of a potential difference

(voltage) across a conductor when it is exposed to a varying magnetic field. It is

described mathematically by Faraday's law of induction, named after Michael Faraday who is

generally credited with the discovery of induction in 1831.

What is a Conductor and Insulator conductor, electric current can flow freely,

in an insulator it cannot. Metals such as copper typify conductors, while most

non-metallic solids are said to be good insulators, having extremely high

resistance to the flow of charge through them(plastic, glass, wood, paper)