Electric Charge and Current - SS1 Physics Lesson Note

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Electric charge and current are fundamental concepts in electricity and are crucial for understanding how electricity flows and behaves. Let's explore each concept in detail:

1. Electric Charge:

Electric charge is a fundamental property of matter. It is responsible for the electromagnetic interactions between particles. Electric charge exists in two types: positive (+) and negative (-). Like charges repel each other, while opposite charges attract each other. The unit of electric charge is the Coulomb (C).

2. Conservation of Charge:

According to the law of conservation of charge, electric charge cannot be created or destroyed; it can only be transferred from one object to another. This means that the total electric charge in a closed system remains constant.

3. Electric Current:

Electric current is the flow of electric charge through a conductor. It is measured in Amperes (A) and is defined as the amount of charge passing through a point in a circuit per unit of time. Electric current can flow in two ways: direct current (DC) and alternating current (AC). In DC, the current flows continuously in one direction, while in AC, the current periodically changes direction.

4. Conductors and Insulators:

Conductors are materials that allow electric charges to flow easily. They have loosely bound electrons that can move freely within the material when a voltage is applied. Examples of conductors include metals like copper and aluminium. Insulators, on the other hand, are materials that do not allow the easy flow of electric charge. They have tightly bound electrons that do not move easily. Materials like rubber, plastic, and glass are insulators.

5. Electric Circuit:

An electric circuit is a closed loop or pathway through which electric current can flow. It typically consists of a power source (such as a battery or generator), conductive wires, and various components such as resistors, capacitors, and switches. A complete circuit allows for the continuous flow of electric charge.

6. Voltage:

Voltage, also known as electric potential difference, is the driving force that pushes electric charge through a circuit. It is measured in Volts (V) and represents the difference in electric potential energy between two points in a circuit. Voltage is responsible for creating the electric field that causes charges to move.

Understanding electric charge and current is fundamental to understanding electricity and its applications in various fields, such as electronics, power generation, and electrical engineering. These concepts form the basis for the study of circuits, electromagnetism, and the functioning of electrical devices.