Electric charge is the fundamental physical property of matter that causes it to experience a force when placed in an electromagnetic field. Understanding its measurement is the first step in studying Electricity (Class 10 Physics).
In nature, electric charge is always 'quantized'. This means you can only have charges that are whole-number multiples of the charge of a single electron (e.g., 1e, 2e, 3e). You cannot have 1.5e.
The SI unit of electric charge is the Coulomb, denoted by the capital letter C.
It is named in honour of the French physicist Charles-Augustin de Coulomb, who discovered Coulomb's Law (the law describing the electrostatic force of attraction and repulsion).
One Coulomb is a massively large quantity of charge. The charge possessed by a single electron is extremely small: -1.6 × 10⁻¹⁹ C.
To make up exactly 1 Coulomb of negative charge, you would need approximately 6.24 × 10¹⁸ electrons (that is 6.24 quintillion electrons!).
Electric charge (Q) is related to Electric current (I) and time (t) by the formula: Q = I × t
Therefore, 1 Coulomb can also be defined as the amount of charge that passes through a conductor when a current of 1 Ampere flows for 1 second (1 C = 1 A·s).
The two types of electric charges are **Positive** (carried by protons) and **Negative** (carried by electrons). Like charges repel each other, and opposite charges attract.
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