SNC 1W1 - Electricity Unit Review

Electricity

A form of energy that results from the interaction of charged particles, such as electrons and protons

Circuit

‘Go around’ - a pathway or closed path around which electricity flows

Electrons Flowing Through A Wire

Water flowing through a hose

Conductors

Materials that allow electrons to flow easily from atom to atom (the human body, the earth)

Insulators

Materials that don’t allow electrons to flow easily (glass, plastic)

Resistors/Semi-conductors

Materials that are in between flowing easily and not easily - can move fairly well (silicon, carbon)

Voltage

The force or pressure of electricity (compared to the amount of water pressure in a hose)

Current (amps)

The amount of electricity (compared to the quantity of water in a hose)

Watts

Work performed by electricity

Charging by Induction

Involves a charged object brought near a neutral object (does not involve negative charges moving from one object to the other)

Negative Charged Rod Brought To Neutral Pith Ball

Negative charges in the ball move away from the negative rod causing charge separation in the ball without making contact

Electrostatic Precipitator

Removes particles from a gas stream by using electrical energy to charge particles either positively or negatively

1 Law of Electric Charge

Like charges repel each other

2 Law of Electric Charge

Unlike charges attract each other (opposites attract)

3 Law of Electric Charge

Charged objects attract uncharged (neutral) objects

Charging by Friction

Begins with two neutral objects made of different materials rubbed against each other (results in two oppositely charged objects ex. clothes rubbing together in a dryer)

Charging by Contact

Involves a charged object touching a neutral object (upon contact, the neutral object acquires the same type of charge as the charged object)

Static

‘stationary’ or ‘at rest’ - electricity that remains on an object and doesn’t move away

Ground

An object that can suppl/remove a very large number of electrons from a charged object-neutralizing the object

Neutralizing

Removing a charge from a charged object to become neutral - can supply electrons to a positively charged object and can remove electrons from a negatively charged object

Voltatic Cell

a source of energy that generates an electric current by chemical reactions that involve two different metals separated by a conducting solution

Battery

a connection of two or more cells

Electrolyte

a solution or paste that conducts charge

2 Electrodes

two metal terminals in a cell or battery

Dry Cells

a cell thar contains an electrolyte that is a paste

Wet Cells

a cell that contains a liquid electrolyte

Primary Cell

can only be used once then it is discarded

Secondary Cell

can be recharged many times

Schematic Circuit Diagrams

simple diagram to represent a circuit

Source of Electrical Energy

A source of electrical energy supply

Electrical Load

A part of a circuit which converts electrical energy into light

Electric Circuit Control Device

A control device that can complete or break the circuit to which it is connected

Connector

A component of a circuit that passes the current very easily from one part of the circuit to another

Open Circuit

no electrons are flowing (no current): switch is open

Closed Circuit

electrons are flowing (current): switch is closed

Terminal

two locations in a cell that must be connected to other components to form a circuit are the positive terminal and the negative terminal

Switch

a switch is a controlled device that is a conductor that can complete or break the circuit it is connected to

Wire

a connecting wire is a conductor that joins different circuit components such as a bulb and a switch

Coulomb (C)

the quantity of charge that is qeual to the charge of 6.25

× 10-18 electrons

Ampere (A)

the unit of electric current, equal to 1 C/s

Electrical Resistance

the property of a substance that hinders electric current and converts electrical energy to other forms of energy

Resistor

a device used in an electric circuit to decrease the current through a component by a specific amount

Load

a resistor or any other device that transforms electrical energy into heat, motion, sound or light

Potential Difference (voltage)

the difference between the electric potential energy per unit of charge at two points in a circuit

Volt

the unit for potential difference equal to 1 J/C. A voltmeter is used to measure potential difference across two points

Ohm’s Law

the ratio of potential difference to current, is a constant called resistance (Ohm: the unit for resistance to one volt per ampere (V/I)

Series Circuit

a circuit in which there is only one path along which electrons can flow

Parallel Circuit

a circuit in which there is more than one path along which electrons can flow

Multimeters

Used as an either an ammeter or a voltmeter, must be connected in parallel with the load