Grade 9 Science: Electricity and Electromagnetic Waves

Vocabulary-style flashcards covering basic electricity terms, formulas, circuit types, and the electromagnetic spectrum based on Grade 9 Science lecture notes.

Electricity

The flow of electric charges (electrons) through a conductor, such as a wire.

Electric Charge ($Q$)

The amount of electricity carried by electrons, measured in Coulombs ($C$).

Current ($I$)

The rate of flow of electric charge, measured in Amperes ($A$).

Voltage ($V$)

The electrical force that pushes charges through a circuit, measured in Volts ($V$).

Resistance ($R$)

The opposition to the flow of electric current, measured in Ohms ($\Omega$).

Conductors

Materials that allow electricity to pass through easily, such as Copper, Aluminium, and Silver.

Insulators

Materials that resist the flow of electricity, such as Rubber, Plastic, Glass, and Wood.

Ohm's Law

The relationship between voltage, current, and resistance expressed by the formulas $V = I \times R$, $I = \frac{V}{R}$, and $R = \frac{V}{I}$.

Current Formula

Calculates the rate of charge flow over time using $I = \frac{Q}{t}$, where $I$ is Current in Amperes ($A$), $Q$ is Charge in Coulombs ($C$), and $t$ is Time in seconds ($s$).

Power Formula

Calculates electrical power using $P = V \times I$, where $P$ is Power in Watts ($W$).

Energy Formula

Calculates electrical energy using $E = P \times t$, where $E$ is Energy in Joules ($J$).

Electric Circuit

A complete path through which electric current flows.

Series Circuit

A circuit with only one path for electricity where current is the same throughout and components are connected one after another.

Parallel Circuit

A circuit with two or more paths for electricity where voltage is the same across each branch and each component works independently.

Electromagnetic (EM) Waves

Waves that carry energy through electric and magnetic fields and do not require a medium, allowing them to travel through space.

Mechanical Waves

Waves that need a medium to travel and cannot travel in space, such as Sound.

Electromagnetic Spectrum

The range of EM waves from longest to shortest wavelength: 1. Radio Waves, 2. Microwaves, 3. Infrared Rays, 4. Visible Light, 5. Ultraviolet Rays, 6. X-rays, 7. Gamma Rays.

Radio Waves

The longest wavelength EM waves used for Communication.

Microwaves

EM waves used for Cooking and Wi-Fi.

Infrared Rays

EM waves used for Remote controls and heat.

Visible Light

The part of the EM spectrum that enables Vision.

Ultraviolet Rays

EM waves used for Vitamin D and sterilization.

X-rays

EM waves used for Medical imaging.

Gamma Rays

Shortest wavelength EM waves used for Cancer treatment.

Wave Energy Relationship

As wavelength decreases, frequency and energy of the wave increase.