Killina Presentation Secondary School

Electricity

Coulomb’s Law states that the force between two point charges is proportional to the product of the charges and inversely proportional to the square of the distance between them.

The Electric Field Strength (E) is the force per unit charge.

The Potential Difference (p.d.) between two point is the work done in bringing a charge of one Coulomb from one point to the other.

The Volt
The potential difference between two points is one volt if one Joule of work is done when bringing a charge of one Coulomb from one point to another.

The potential at a point refers to the work done in bringing unit charge from that point to earth.

The Capacitance of a conductor is the ratio of the charge on a conductor to its potential.

Current is a flow of charge.

1 Amp = 1 C / s

A voltage when applied to a circuit is an emf .

The resistance of a conductor is the ratio of the Potential Difference across it to the current flowing through it.

Ohm’s Law states that the current flowing through a conductor is directly proportional to the Potential Difference across it, assuming constant temperature.

Resistivity is the (Resistance X Area) / length

Joules Law states that the rate at which heat is produced in a conductor is proportional to the square of the current, provided its resistant is constant