Electric Current

The flow of electric charge is known as electric current. Electrons move through a conductor to carry electric current. Current electricity is the flow of electric charge, similar to how water flows in a river. It is the energy that powers electrical devices like bulbs, appliances, and the wiring in our homes.

1. Current (I): Current is defined as the amount of electric charge ($Q$) that flows through the cross-section of a conductor in unit time (t).

I=`"Q"/"t"`

2. Electric circuit: An electric circuit is a continuous and closed path of an electric current.

3. Direction of Current: While electrons move from the negative terminal to the positive terminal of a cell, the conventional direction of current is considered opposite to this, flowing from the positive terminal to the negative terminal.

SI Unit of Electric Charge:

• The unit of charge in SI units is coulomb (C). Current is expressed in amperes (A). The charge of one electron is 1.6×10⁻¹⁹ C
• Ampere: A conductor flows one ampere of current if one coulomb charge passes through it every second. 1A=`"1C"/"1s"`

Very small values of current are expressed in the following units:

• 1 mA (milliampere) = 10⁻³ A
• 1 μA (microampere) = 10⁻⁶ A

These smaller units are used when dealing with tiny currents, such as those in electronic circuits or devices like mobile phones and sensors.

Current is defined as the rate of flow of charge.

A continuous and closed path of an electric current is called an electric circuit.

• Electricity is a convenient and controllable form of energy widely used in homes, industries, schools, and hospitals.
• Electric current is produced when electric charges flow through a conductor, and it flows only through a closed, continuous electric circuit.
• A switch completes or breaks the circuit; when the circuit is broken, current stops flowing, and devices like bulbs do not glow.
• Electric current is the rate of flow of charge, given by the relation I = Q / t, where Q is charge and t is time.
• In metallic wires, electrons are the charge carriers, but by convention, current flows from the positive to the negative terminal, in the opposite direction to electron flow.