Electricity and simple circuit, ohlm's law

physics 10 - L1

It states that electric current flow is directly proportional to voltage and inversely proportional to its resistance.

What is Ohm’s Law?

Equation for voltage

V = I x R

V/R

equation for current

V/I

equation for R

Definition of voltage

the electrical potential difference or energy/pressure that pushes the charges through a electric circuit.

definition of current

rate of flow of electric charge

definition of resistance

the /opposition’ to the flow of current in a circuit.

closed simple circuits

everything is connected = the circuit is functioning

open simple circuits

there is a broken gap in the circuit = can not work

Factors affecting resistance = LENGTH

Direct relationship with resistance

• Longer = more resistance

• shorter = less resistance

Factors affecting resistance = THICKNESS

Inverse relationship with resistance

• Thicker = less resistance

• Thinner = more resistance

Factors affecting resistance = MATERIAL

Direct relationship with resistance

• higher resistivity = more resistance

• ex. Copper < Nichrome < Rubber

Conductors vs Insulators

Conductors = low resistivity (copper, silver)

Insulators = high resistivity (rubber, glass)

Factors affecting resistance = TEMPERATURE

Direct relationship with resistance 

• increasing temperature cause more atoms to collide = hinders the flow of electrons in conductors, and conversely, the increased energy can free up more charge carriers in semiconductors