Current Electricity Grade 9 Science

Amps

unit of current; A= C/s

Voltage

The potential difference measured in volts. The amount of work to be done to move a charge from one point to another along an electric circuit.

Volts

Unit for electric potential difference

Voltmeter

instrument that measures potential difference

ammeter

instrument used to measure current

series circuit

A circuit in which all parts are connected end to end to provide a single path of current.

parallel circuit

A closed circuit in which the current divides into two or more paths before recombining to complete the circuit

resistance

A material's opposition to the flow of electric current.

electrical energy

Energy made available by the flow of electric charge through a conductor; equal to power x time

high resistance due to large length and small Area

Resistance of long, thin wire

low resistance due to small length and large Area

Resistance of short, fat wire

power source

Provides the voltage for the circuit.

load

the materials carried by a stream

lamp

light source

Conducting wire (conductor)

allows electrons to flow freely based on their loose hold of valence electrons

electric circuit

a complete, unbroken path through which electric charges can flow

mechanical energy

Kinetic or potential energy associated with the motion or position of an object

heat

the energy transferred between objects that are at different temperatures

schematic diagram

a way to represent a circuit on a piece of paper

series circuit

A circuit in which all parts are connected end to end to provide a single path of current.

parallel circuit

A circuit that contains more than one path for current flow.

current

A flow of electric charge.

DC

discharge

Amps (A)

The unit of measurement for current (amount of charge/sec)

Charge

A measure of the extra positive or negative particles that an object has.
current x time

Coulombs (C)

unit of charge

electrons

negatively charged particles

ammeter

A device used to measure current in a circuit

Voltmeter

A device used to measure voltage, or electrical potential energy difference

potential difference (voltage)

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

Resistance

the characteristic of a material that slows electron flow
units are measured in ohms

resistor

An electrical device that resists the flow of electrical current

Ohms law

V=IR

open and closed circuit

circuit open = device off
circuit closed = device on

how to measure voltage

charge in energy divided by coulombs

Current symbol

I (A)

Charge symbol

Q

Time symbol

T

how to caculate current ( I )

Q divided by T
colombs divided by time

caculate time ( T )

Q divided by I
coulombs divided by current

caculate charge ( Q )

current x time

caculate resistance

Voltage divided by Current
V divided by I

A load had 2 A of current flowing through it. The voltage across the load is 6.0 V. Calculate the resistance

R = V divided by I
R = 6.0 divided by 2 = 3

A 12 ohm resistor is connected to a power supply set at 6 V. Calculate the current going though the resistor

I = R divided by V
I= 6 divided by 12 = 2

Resistance formula

R= V divided by
I = R divided by V

Voltage formula

V=IR

How much time does it take for 80 C to pass through a light that draws on 40 A?

80 divided by 40 = 2mins

1 minute

60 seconds (turn it into seconds)