Incandescent Bulb: Parts, Energy Transformation, and Electrical Circuits

Incandescence

Incandescence is when light is produced by heating a material until it glows.

Main parts of an incandescent bulb

Glass bulb, Filament, Support wire, Base cap, Inert gas, Contact wires.

Forms of energy

Kinetic - moving objects (rolling ball), Potential - stored energy (book on shelf), Thermal - heat (boiling water), Chemical - stored in food, batteries, Electrical - moving charges (lamp), Mechanical - movement/position (swing), Nuclear - atom's nucleus (sun), Light - light sources (bulb), Sound - vibrations (music).

Principle of conservation of energy

Energy cannot be created or destroyed; it only changes form.

Efficiency formula

Efficiency = (Useful energy ÷ Input energy) × 100%

Bouncing ball energy transformation

Potential → Kinetic → Potential (Up and down motion)

Light bulb energy transformation

Electrical → Light + Heat (Bulb glows and warms up)

Car energy transformation

Chemical → Mechanical + Heat (Fuel moves car)

Guitar energy transformation

Mechanical → Sound (String vibrations)

Solar panel energy transformation

Light → Electrical (Converts sunlight)

Hammer energy transformation

Mechanical → Kinetic + Sound + Heat (Transfers energy to nail)

Main parts of a circuit

Source (Provides electrical energy), Closed Path (Allows current flow), Device (Uses energy - bulb, motor).

Benefits of circuit diagrams

Clear, universal, easy to design, understand, and repair circuits.

Common symbols in circuits

DC source, bulb, switch, ammeter, voltmeter.

Difference between electron flow & conventional current

Electron Flow: Electrons flow - to +; Conventional Current: Positive charges flow + to -.

Current unit, symbol, instrument

Ampere (A), symbol: I, measured by an ammeter.

DC vs AC

DC: One direction, Battery; AC: Alternates, Mains electricity.

Polarity

Positive = current flows out, Negative = current flows in. It shows current direction.

Series connection

Only one path for current. If one bulb breaks, all stop. Dimmer bulbs.

Parallel connection

Multiple paths for current. Each bulb gets full voltage. Brighter, but uses more wires.

Batteries in series

Voltages add up (e.g., 1.5V + 1.5V = 3V).

Ohm's Law

I = V / R → Current = Voltage ÷ Resistance.

Brightness rules

Higher voltage → brighter; Higher resistance → dimmer; Higher current → brighter.

Conductor vs Insulator

Conductor - lets current flow easily (metal); Insulator - blocks current (plastic, rubber).

Unit of resistance

Ohm (Ω).

Resistance effect in series circuit

Higher resistance = lower current.

Electrical Power definition

Rate at which energy is transformed or used per second.

Unit of power

Watt (W).

Power formula

P = IV or P = V² / R.

Energy use measurement

Measured in kilowatt hours (kWh).