SCIENCE

incandescent bulbs

Incandescence

When light is produced by heating a material until it glows.

Main parts of an incandescent bulb

Glass bulb, Filament, Lead in wires, Base

Forms of energy

Kinetic, Potential, Thermal, Chemical, Electrical, Mechanical, Nuclear, Light, Sound, Gravitatinal

Principle of conservation of energy

Energy cannot be created or destroyed; it can only be transformed into other forms or transferred to other objects.

Efficiency

The measure of how well energy is converted from one form to another in a process or device.

Main parts of a circuit

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

Benefits of circuit diagrams

Clear representation, universal, easy to design and plan, easy to read

Electron Flow

Negative terminal —> Positive terminal

Electron carry negative charge, so they move toward the positive terminal

Conventional Current

Positive terminal —> Negative terminal

Historically, current was defined before electrons were discovered

Direct Current (DC)

Steady, one way flow (—-) from sources like batteries.

Alternative Current (AC)

Current that alternates back and forth (~) from sources like generators.

Source Polarity

Reversing the polarity of a source reverses the direction of the current (clockwise to counterclockwise)

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).