B.5 Current and circuits

Physics 11

Law of Conservation of Electric Charge

Charge is never made or destroyed, it is only transferred from one material to another.

Potential difference

the energy transformed (work done) per unit positive charge (1C) in moving the charge between two points (V = W/Q)

Electromotive force (emf):

the amount of electrical potential energy gained per unit charge as it passes through the battery.

Current

the rate of flow of electric charge (I=Q/t)

Resistance

ratio of the p.d. across a conductor to the current flowing through it (R = V/I)

Ohm’s law

The current flowing through a conductor is proportional to the potential

difference across it providing the temperature remains constant

Power

Rate of transformation of energy (P=W/t)

Current Formula

Potential difference Formula

Resistance Formula

Resistivity Formula

Power Formula

Electromotive force (EMF) Formula

Potential Difference Series Formula

Resistance Series Formula

Current Series Formula

Resistance Parallel Formula

Potential Difference Parallel Formula

Current Parallel Formula