Railway Science (Physics-Electric Current and its Effects) (Part-IV)

In a series circuit, all components are connected end to end to form a single path for current flow. Formula for calculating resistance in series Rₛₑᵣᵢₑₛ= R₁ + R₂ + R₃ + …+Rₙ . In a parallel circuit, all components are connected across each other with exactly two electrically common nodes with the same voltage across each component. So, even if one of the bulbs blows out, the other bulbs will continue to glow. Formula for calculating

A measure of the opposition to current flow in an electrical circuit. It is measured in ohms (Ω). Charge is a property of a substance that causes it to experience a force when placed in an electric field or a magnetic field. It can be positive as well as negative. SI unit of charge - Coulomb. Current is a flow of electrical charge carriers, usually electrons or electron-deficient atoms.

Good conductor of electricity. It is ductile and can be drawn into thin wires. Due to their metallic properties, It contains a large number of free electrons and allows electricity to flow through them. Conductors of electricity - Copper (Cu), Aluminium (Al), Silver(Ag), Gold (Au), Graphite, Platinum (Pt).

(Variable resistance):- Current controlling device, used for controlling the flow of electric current either by increasing or decreasing the resistance. Cell:- Single unit of device that converts chemical energy into electrical energy. Switch :- Any device used to interrupt the flow of electrons in a circuit. Resistor (R):- Regulating the flow of electric current in electrical circuits. The SI unit of resistance and resistivity is ohm (Ω) and ohm-metre respectively.

Ohm's law states that the potential difference across a metal wire is proportional to the current flowing through it, and directly proportional to the resistance of the circuit. The constant of proportion is called resistance. The SI unit of resistance is ohms (Ω). Mathematically expressed: V = IR. Where V is the potential difference (voltage), I is the current, and R is the resistance of the conductor.

An electrical component that limits or regulates the flow of electrical current in an electronic circuit. Insulators - materials that do not allow electric charges to flow freely through them. Example - Plastic, Wood, Rubber, Ceramics. Semiconductors - materials which have a conductivity between conductors (generally metals) and nonconductors. Example - Silicon (Si), germanium (Ge), tin (Sn), selenium (Se), tellurium (Te). Conductors - materials that allow electric current to flow easily. Silver is the best conductor of electricity, as the metal has more free electrons to transfer electric energy.

A voltmeter is an instrument used for measuring electric potential difference between two points in an electric circuit. It is connected in parallel across the circuit to measure the voltage. Ammeters used to measure current in a circuit. It is connected in series and has low resistance.

It is a device that converts chemical energy into electrical energy and maintains a potential difference between its two terminals. A rheostat is a variable resistor used to control the flow of current in a circuit by changing its resistance. An ammeter is a device used to measure the current flowing in a circuit. A voltmeter is a device used to measure the potential difference between two points in a circuit.

Polymer made of phenol and formaldehyde, It is a thermosetting polymer which is also an insulator. Conductor - Materials that permit electricity or heat to pass through it, like silver, aluminum, gold. Insulator - Materials that do not permit heat and electricity to pass through it, have low electrical conductivity, like:- paper, wood, rubber are examples of insulators.

Materials that do not allow electricity to easily pass through them. Examples - Wood, Rubber, Glass, Sand . Distilled water - A type of purified water that does not contain any dissolved salts or other impurities, as it does not have any ions that can carry an electrical charge.