Current & Charge

A conductor is a substance which allows charge to flow through it. Example: any metal.

An insulator is a substance that doesn't allow charge to flow through it. Example: plastic, rubber, wood, glass.

Electrostatic forces are forces of attraction and requisition between protons and electrons.

Electric current is flow of electric charge (I)

Circuit is the path around which an electric current flows.

Effects of electric current

• Heating Effect: heat produce at every point but mainly bulb.
• Chemical Effect: bubbles of gas an rxn takes place in beaker.
• Magnetic effect: the magnetic compass needle deflects from normal N-S position due to magnetic field around the wire

Electric current in a metal is a flow of electrons

Electric current is charged particles moving

Current is the amount of charge passing per second.

Ampere (A) = SI Unit

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• Positive & Negative terminals in battery
• Current is understood as conventional current flowing from positive to negative.

Ampere - The current which when flowing in two straight parallel conductors of infinite length, placed on metre apart in a vacuum, would produce a force of 2×10-7 Nm-2

Direct Current (d.c.) current that flows in one direction only caused by battery or chemical cell

Alternating Current (a.c.) current that reverse direction 100 times per second i.e. every 1/100th of a second caused by main electricity supply.

*Current flowing out of battery = Current flowing in Ammeter connected in series with parts of circuit in which the current is flowing.

In series: $I_1 = I_2 = I_3 = I_{Total}$

In Parallel: $I_1 + I_2 = I_{Total}$

Current splits at junction

Splits equally if the paths were made up of identical pieces of wire i.e. the resistance was equal