Physics ohm’s law

It is the rate of flow of electric

charge through a medium.

This charge is typically carried by

moving electrons in a conductor

such as wire.

Current flows from negative to

positive on the surface of a conductor. It is measured in

amperes or amps.

A circuit needs three

things to work:

1. Power source

2. A closed conductive

path

3. Resistor/Load

Also called as:

Electric Potential difference

Potential drop

Electrical potential

difference and;

Electrical potential

Voltage is the difference

in electrical potential

between two points, or

the difference in

electrical potential

energy unit charge

between two points.

Resistance is how much an

object resists the flow of

electrons.

It is the inverse of conductance.

It measures how difficult it is for

electrons to flow through a

material. It is measured in

ohms.

Conductor – a material which

contains movable electrical

charges. In metallic

conductors such as copper

and aluminum, the movable

charged particles are

electrons

Insulator – a material that is

a poor conductor of

electricity.

›An insulator, such as

ceramic or rubber, has high

resistance and poor

conductance. A metal has

low resistance and high

conductance

Resistors – objects that

are designed to have

a specific resistance

so that they can

dissipate electrical

energy or modify how

a circuit behaves

The nature of the material = Some

materials are better conductors than

others, causing less resistance

The thickness of the conductor/wire =

The larger the wire, the less resistance;

the bigger the cross-sectional area of

the wire the greater the number of

electrons that experience the ‘electric

slope’ from the potential difference.

The length of the

conductor/wire

= The longer the

wire, the more

resistance. The

longer the wire,

the less the volts

each

centimeter of it

will get.

The temperature =

Heat affects resistance; the

higher the

temperature, the higher the

resistance

Ohm’s Law describes

mathematically the

relationship between

current and voltage

(potential difference).

I is the current through the

conductor in units of

amperes;

V is the potential difference

measured across the

conductor in units of volts;

and

R is the resistance of the

conductor in units of ohms.

The potential difference

(voltage) is

proportional to the

current through it. The

current is indirectly

proportional to

resistance.