1. Examples of Electrical Lighting and Their Functions:
o Incandescent Bulbs:
-Produce warm light
-Commonly used in household settings
-Not very efficient.
o LED lights:
-Used in homes, street lights, and devices
-LEDs are energy-efficient
-Last longer than incandescent bulbs.
o Fluorescent Tubes:
-Often used in commercial spaces
-More efficient than incandescent bulbs
-But tend to emit (give) a cooler, less natural light.
2. Define Incandescence:
o Incandescence = The emission of visible light from a hot
body / visible light emitted from a hot body
3. Main Parts of an Incandescent Bulb
o Filament: Thin wire that heats and glows to produce light.
o Glass Bulb: Protects the filament
o Connection to fitting: To connect one component to
another component
o Fitting: Allows the bulb to connect to the electrical supply/
Provides an electrical connection.
Energy Transformation ✅
1. Forms of Energy:
o Kinetic Energy: (e.g., a rolling ball).
o Thermal Energy: (e.g., a stovetop).
o Chemical Energy: (e.g., batteries, gasoline).
o Electrical Energy: (e.g., power lines).
o Light Energy: (e.g., sunlight).
o Sound Energy: (e.g., music).
2. Qualitative Energy Transformations:
o Car Engine: Converts chemical energy from fuel into
thermal energy and kinetic energy (engine movement).
o Toaster: Converts electrical energy into thermal energy
to toast bread.
o Solar Panel: Converts light energy into electrical energy.
3. Quantitative Transformations Using Sankey Diagrams:
o Sankey Diagrams:
o Width of the arrow= The number/ worth
o Horizontal arrow= Energy used (Joules used)
o Vertical arrow= Energy wasted
4. Principle of Conservation of Energy:
, o Energy cannot be created or destroyed. It can only be
transformed from one form to the other
5. Efficiency:
o Deinition: Using the least amount of inputs to achieve the
highest amount of output
UsefulOutput energy
Efficiency= x= x 100 %
Total Input energy
6. Analyzing Efficiency with Sankey Diagrams:
o The width of useful energy arrows v.s. The width of wasted
energy arrows.
Electric Circuits✅
1. Roles of Source, Closed Path, and Device:
o Source: Provides electrical energy (e.g., a battery).
o Closed (Conducting) Path: Allows current flow and
transports energy (e.g., wires).
o Device: Uses the energy (e.g., a bulb).
With these components current can flow
2. Benefits of Circuit Diagrams:
o Clear and concise
o Only describe/contain the essential electrical information
o Unambigiuous
3. Recognize Electrical Symbols:
o Symbols include DC source, incandescent bulb, switch,
ammeter, and voltmeter.
4. Transform Pictures to Diagrams:
o Draw components in accurate positions, indicating current
direction.
5. Be able to identify and illustrate two types of circuits
Current✅
1. Electron Flow vs. Conventional Current:
o Electron flow: Actual flow of electrons, negative to positive.
o Conventional current: Flows from positive to negative.
2. Unit and Measurement of Current:
o Current (symbol: III) is measured in amperes (A) using an
ammeter.
3. DC vs. AC:
o Direct Current (DC)= current flows in one direction
o Alternating current (AC)= current changes it direction
periodically
4. Effect of Source Polarity on Current: