Ohm's Law and Resistors - SS1 Physics Lesson Note

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Ohm's Law and resistors are fundamental concepts in the study of electricity and are essential for understanding the relationship between current, voltage, and resistance. Let's delve into each concept:

1. Ohm's Law:

Ohm's Law states that the current flowing through a conductor is directly proportional to the voltage applied across it and inversely proportional to the resistance of the conductor. Mathematically, Ohm's Law is expressed as:

V = I × R

where V represents the voltage across the conductor (measured in volts, V), I represents the current flowing through the conductor (measured in amperes, A), and R represents the resistance of the conductor (measured in ohms, Ω).

Ohm's Law shows that as the voltage across a conductor increases, the current flowing through it also increases if the resistance remains constant. Similarly, if the resistance increases, the current decreases for a given voltage.

2. Resistors:

A resistor is an electrical component designed to have a specific resistance value. It is used to control and limit the flow of electric current in a circuit. Resistors are typically made of materials with high resistance, such as carbon, metal, or a combination of materials. The resistance of a resistor is determined by its physical properties, such as length, cross-sectional area, and resistivity.

Resistors are represented by specific colour-coded bands that indicate their resistance value. The resistance is measured in ohms (Ω). Common resistor values include 1kΩ (1000 ohms), 10kΩ (10,000 ohms), and 100kΩ (100,000 ohms).

Resistors are used in various applications, such as voltage division, current limiting, signal conditioning, and temperature sensing. They play a crucial role in designing and controlling electrical circuits.

Understanding Ohm's Law and the function of resistors allows us to predict and manipulate the behaviour of electric circuits. It enables us to calculate current, voltage, and resistance values and design circuits to meet specific requirements. These concepts are essential in fields such as electronics, electrical engineering, and circuit design.