Measurement of electricity

Electromotive force (voltage)

1. Voltage is the force that makes electricity flow in a circuit. It is like a push that moves electric charges through the wires.
2. It is measured in volts (V) using a device called a voltmeter.

Electric current

1. The flow of electricity in a circuit is called an electric current, represented by the letter I.
2. It is measured in amperes (A) using a device called an ammeter.

Electric current is the flow of electric charges through a conductor, like a wire, in a circuit. It's similar to the flow of water in a pipe. The stronger the voltage, the greater the current.

Conductors and insulators

1. A conductor is a material that allows electricity to pass through it easily. Examples: Metals like copper, silver, and aluminum.
2. An insulator is a material that does not allow electricity to flow through it. Examples: Wood, rubber, plastic, and glass.

Resistance

Resistance is the opposition to the flow of electric current in a circuit. It controls how much electricity flows through a device. For example, in a bulb, resistance limits the current to ensure the bulb doesn't burn out.

1. When electricity flows in a circuit, some materials resist its flow. This resistance is called resistance, and it is represented by the Greek letter Ω (ohm).
2. The device used to measure resistance is called an ohmmeter.
3. Resistance slows down the current and ensures the circuit works safely.

Devices and Their Symbols

Electric circuits use specific devices to measure voltage, current, and resistance. These devices are:

1. Voltmeter: Measures voltage (V).

2. Ammeter: Measures electric current (A).

3. Ohmmeter: Measures resistance (Ω).