Electricity

Ø Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge.

Ø In the early days, electricity was considered as being unrelated to magnetism.

Electric Current :

Ø Electric current is often termed as ‘current’ and it is represented by the symbol ‘I’.

Ø It is defined as the rate of flow of charges in a conductor.

Ø This means that the electric current represents the amount of charges flowing in any cross section of a conductor (say a metal wire) in unit time.

Symbols of some components of a circuit -

Resistivity of some materials –

Resistors in series :

Ø A series circuit connects the components one after the other to form a ‘single loop’. A series circuit has only one loop through which current can pass.

Ø If the circuit is interrupted at any point in the loop, no current can pass through the circuit and hence no electric appliances connected in the circuit will work.

Ø Series circuits are commonly used in devices such as flashlights.

Ø Thus, if resistors are connected end to end, so that the same current passes through each of them, then they are said to be connected in series.

Resistances in Parallel :

Ø A parallel circuit has two or more loops through which current can pass.

Ø If the circuit is disconnected in one of the loops, the current can still pass through the other loop(s).

Ø The wiring in a house consists of parallel circuits.

Differences between series and parallel –

MIND MAP