Electricity Fundamentals

Electricity in Modern Life

• Electricity is a controllable and versatile form of energy used in various domains such as homes, schools, hospitals, and industries.

Electric Current

• Electric current represents the movement of electric charges through conductors like metallic wires.
• Electric current is measured in amperes (A) and denotes the rate of flow of electric charges.
• The unit of electric charge is the coulomb, with one coulomb equivalent to approximately 6 × 10^18 electrons.
• An ammeter, connected in series in a circuit, measures electric current, displaying the flow from the positive to the negative terminal of a cell through components like bulbs.

Flow of Electric Charges

• Electrons, negatively charged particles, are the actual carriers of current.
• In metals, electrons move with an average speed despite encountering resistance from atoms within the solid conductor.
• Despite relatively slow motion, the current itself flows nearly at the speed of light, allowing devices such as bulbs to instantaneously illuminate upon activation.

Electric Potential Difference

• Electric potential difference, analogous to pressure difference in fluid flow, drives the movement of charges within a conductor.
• The unit of potential difference is the volt (V), named after Alessandro Volta.
• A voltmeter, connected in parallel to the components being measured, quantifies the potential difference between two points in a circuit.

Circuit Diagrams and Ohm's Law

• Circuit diagrams, represented with symbols, elucidate the components of an electric circuit, simplifying comprehension and analysis.
• Ohm's Law elucidates the relationship between potential difference across a conductor and the current through it, establishing a direct proportionality between the two.

Resistance

• Resistance, a constant characteristic of a given conductor, quantifies its opposition to current flow.
• Factors influencing resistance include length, cross-sectional area, and material composition.
• Resistors can be connected in series or parallel, with each configuration impacting the total resistance and current flow differently.

Heating Effect of Electric Current

• The heating effect of electric current arises as current flows through a conductor, generating heat due to resistance.
• This phenomenon finds practical applications in devices like electric heaters and toasters, where electrical energy is converted into heat for various purposes.