Current Electricity

Question 1

Electric current

Answer 1

Electrons flowing through a circuit generating electricity

Question 2

Current electricity

Answer 2

The controlled flow of electrons through a conductor

Question 3

Electric circuit

Answer 3

A continuous path in which electrons can flow

Question 4

Source

Answer 4

The resources for electric power (EX. electric cell, three-cell battery, DC power supply, etc.)

Question 5

Load

Answer 5

The part of an electric circuit that converts electrical energy into other forms of energy (EX. lamp, electric motor, etc.)

Question 6

Control device

Answer 6

The part of an electric circuit that controls the energy flow from the source to the load (EX. a switch)

Question 7

Direct current (DC)

Answer 7

A flow of electrons in one direction through an electric circuit

Question 8

Alternating current (AC)

Answer 8

A flow of electrons that alternates in direction in an electric circuit

Question 9

Series circuit

Answer 9

A circuit in which the loads are connected end to end so that there is only one path for electrons to flow

Question 10

Parallel circuit

Answer 10

A circuit in which the loads are connected by branches so that there are two or more paths for electrons to flow

Question 11

Conductor

Answer 11

A material that lets electrons move easily through it (EX. silver, copper, etc.)

Question 12

Insulator

Answer 12

A material that does not easily allow the movement of electrons through it (EX. plastic, rubber, etc.)

Question 13

Current (I)

Answer 13

A measure of the rate of electron flow past a given point in a circuit; measured in amperes (A)

Question 14

Potential difference (voltage) (v)

Answer 14

The difference in electrical potential energy per unit charge measured at two different points; measured in volts

Question 15

Resistance (R)

Answer 15

The ability of a material to oppose the flow of electric current; measured in ohms (Ω)

Question 16

Primary cell

Answer 16

An electric cell that may only be used once

Question 17

Secondary cell

Answer 17

An electric cell that can be recharged

Question 18

Watt

Answer 18

The unit of measurement for electrical, one watt is equal to one Joule per second
(W=J/s)

Question 19

Kilowatt-hour (KW-h):

Answer 19

The SI (metric) unit for measuring electrical energy usage; the used of one kilowatt of power for one hour

Question 20

Efficiency

Answer 20

Comparison of the energy output of a device with the energy supplied

Question 21

What do simple electric circuits typically contain

Answer 21

An energy source, a load, conducting wires and sometimes, a switch

Question 22

Points about electrical energy

Answer 22

• electrical energy is measured in joules (J)
• electrical devices use electrical energy to do work
• work occurs when one form of energy is converted into another form of energy

Question 23

Examples of sources of electrical energy

Answer 23

• batteries

- electric generating stations

Question 24

Advantages of hydro-electric dams

Answer 24

• will never run out of this electricity source
• many possible locations for generating stations
• small-scale hydro-electric projects are in good shape

Question 25

Disadvantages of hydro-electric dams

Answer 25

- dams change the way water flows - changes ecology of a watershed - land may become flooded - disrupts fish migration - blocks salmon from reaching spawning grounds - costs are high for both consumers and construction/operation

Question 26

Review all photos

Answer 26

In iPhoto's

Question 27

What is current electricity

Answer 27

Electric charge that is moving (the electrons are flowing from one atom to the other atom)

Question 28

What is a moving charge called

Answer 28

Electric current

Question 29

What is an electric circuit

Answer 29

A controlled path through which electric current passes; used to convert electrical energy into other forms of energy

Question 30

Ammeter

Answer 30

A device used to measure electric current | **must be connected in series**

Question 31

Voltmeter

Answer 31

A device used to measure potential difference (voltage) | **must be connected in parallel with the load**

Question 32

Ohmmeter

Answer 32

A device used to measure resistance | **must be connected in parallel with the load**

Question 33

Factors that affect resistance

Answer 33

1. Type of material 2. Cross sectional area 3. Length 4. Temperature

Question 34

Type of material

Answer 34

The ability of a material to conduct electricity (how freely electrons can move)

Question 35

Cross sectional area

Answer 35

Thicker wires have less internal resistance (electrons have more room to move)

Question 36

Length

Answer 36

Longer wires have more resistance (electrons have to travel through more material)

Question 37

Temperature

Answer 37

When the temperature increases, vibrations increase causing more collisions with electrons and more resistance

Question 38

Resistor

Answer 38

A device that reduces the flow of electric current Symbol in photos

Question 39

Examples of resistors

Answer 39

- lamps with more than one setting - dimmer switches in the wall - volume controls on a stereo

Question 40

Ohm's law definition

Answer 40

The straight-line relationship between voltage and current

Question 41

What is ohms law

Answer 41

As the potential difference (v) across a load increases, so does the current

Question 42

Formula for ohm's law

Answer 42

R=V/I | Looks in photos

Question 43

Grass method

Answer 43

``` Given Required Apply equation Solution Statement ```

Question 44

Loads in series

Answer 44

More loads, more resistance, less current More identical lamps connected in series means less of an electron's electric potential energy gets converted into heat and light

Question 45

Loads in series formula

Answer 45

Look in photos V= V source/# of loads

Question 46

Loads in parallel

Answer 46

More loads, more paths electrons have to follow

Question 47

Loads in parallel formula

Answer 47

I Load= I source/# of loads