Science Exam Review: Physics

Amplitude

The wave's height above the rest position.

Frequency (f)

The rate at which a wave repeats.

Wavelength

The distance from one crest to the next crest.

Crest

The highest point of a wave.

Trough

The lowest point of a wave.

Radio Waves

Electromagnetic waves used for long-distance communication.

Microwaves

Electromagnetic waves with wavelengths shorter than radio waves but longer than infrared waves.

Infrared

Electromagnetic radiation with wavelengths longer than visible red light but shorter than microwaves.

Visible Light

The portion of the electromagnetic spectrum visible to the human eye.

Ultraviolet (UV)

Electromagnetic radiation with wavelengths shorter than visible violet light but longer than X-rays.

X-Rays

High-energy electromagnetic radiation with wavelengths shorter than UV rays but longer than gamma rays.

Gamma Rays

The highest-energy electromagnetic radiation produced by radioactive decay.

Order of the Electromagnetic Spectrum (Longest to Shortest Wavelength)

Radio Waves, Microwaves, Infrared, Visible Light, Ultraviolet, X-Rays, Gamma Rays.

Natural Light

Light produced by sources not created by humans.

Artificial Light

Light produced by human-made sources.

Medium

A physical substance through which energy can be transferred.

Radiation

A method of energy transfer that does not require a medium.

Electromagnetic Wave

A wave with electric and magnetic components that travels at the speed of light and does not require a medium.

Visible Spectrum

The continuous sequence of colours that make up white light.

Luminous

Produces its own light.

Non-Luminous

Incandescence

The production of light due to high temperature.

Luminescence

The production of light without heat.

Electric Discharge

The production of light by passing an electric current through a gas.

Phosphorescence

The emission of visible light over time after absorbing ultraviolet light.

Fluorescence

The immediate emission of visible light after absorbing ultraviolet light.

Chemiluminescence

The production of light from a chemical reaction with little or no heat.

Bioluminescence

The production of light by living organisms through a chemical reaction.

Triboluminescence

The production of light by rubbing, crushing, or scratching certain crystals.

Light-Emitting Diode (LED)

Produces light when electric current flows through a semiconductor.

Semiconductor

A material that allows electric current to flow in only one direction.

Normal

A line drawn perpendicular to a surface.

Incident Ray

The incoming ray of light that strikes a surface.

Reflected Ray

The ray of light that bounces off a surface.

Angle of Incidence

The angle between the incident ray and the normal.

Angle of Reflection

The angle between the reflected ray and the normal.

Law of Reflection

The angle of incidence equals the angle of reflection.

Light Ray

A line representing the direction of light travel.

Geometric Optics

The study of light behavior using ray diagrams.

Incident Light

Light that strikes an object.

Transparent

A material that transmits almost all incident light.

Translucent

A material that transmits some light but scatters it.

Opaque

A material that transmits no light.

Image

A reproduction of an object formed by light.

Mirror

A polished surface that reflects light.

Reflection

The bouncing back of light from a surface.

Plane Mirror

A flat mirror.

Perpendicular

Meeting at right angles (90°).

Regular (Specular) Reflection

Reflection from a smooth surface.

Diffuse Reflection

Reflection from a rough or irregular surface.

Virtual Image

An image formed where light appears to come from.

Real Image

An image formed where light actually converges and can be projected onto a screen.

Lateral Inversion

The left-right reversal seen in a plane mirror.

Concave Mirror

A converging mirror with an inward-curved reflective surface.

Convex Mirror

A diverging mirror with an outward-curved reflective surface.

Centre of Curvature

The center of the sphere from which a curved mirror is formed.

Principal Axis

The line passing through the center of curvature and the vertex.

Vertex

The point where the principal axis meets the mirror.

Converge

To meet at a common point.

Diverge

Focus

The point where parallel rays converge after reflection from a concave mirror.

Index of Refraction

The ratio of the speed of light in a vacuum to its speed in a medium.

Refracted Ray

The outgoing ray after light enters a new medium.

Angle of Refraction

The angle between the refracted ray and the normal.

Refraction

The bending of light when it passes from one medium to another.

Why Refraction Occurs

Because light changes speed when entering a different medium.

Apparent Depth

The depth an object appears to have because of refraction.

Cornea

The clear front surface of the eye that protects it and helps focus light.

Iris

The coloured muscular structure that controls pupil size.

Pupil

The opening in the iris through which light enters the eye.

Lens

The transparent structure that focuses light onto the retina.

Retina

The layer of light-sensitive cells at the back of the eye.

Optic Nerve

The bundle of nerves that carries visual information to the brain.

Function of the Cornea

Protects the eye and begins focusing incoming light.

Function of the Iris

Controls how much light enters the eye.

Function of the Pupil

Allows light to enter the eye.

Function of the Lens

Focuses light onto the retina.

Function of the Retina

Detects light and converts it to nerve signals.

Function of the Optic Nerve

Carries signals from the retina to the brain.

Myopia

Correction for Myopia

Hyperopia

Far-sightedness; difficulty seeing nearby objects.

Correction for Hyperopia

A converging (convex) lens.

Presbyopia

Age-related far-sightedness caused by reduced lens flexibility.

Correction for Presbyopia

A converging lens or reading glasses.

Examples of Natural Light Sources

The Sun, stars, lightning, fireflies.

Examples of Artificial Light Sources

Light bulbs, LEDs, neon signs, televisions.

Example of Incandescence

A glowing filament in a traditional light bulb.

Example of Fluorescence

Fluorescent lights and highlighter ink.

Example of Phosphorescence

Glow-in-the-dark stickers.

Example of Chemiluminescence

Glow sticks.

Example of Bioluminescence

Fireflies and some deep-sea organisms.

Example of Triboluminescence

Light

Energy that travels in waves and is carried by particles called photons.

Photon

A small bundle of energy that carries light.

Electromagnetic Wave

A wave made of oscillating electric and magnetic fields.

Electromagnetic Radiation

Energy carried by electromagnetic waves.

Speed of Light in a Vacuum

3.0 × 10⁸ m/s.

Electromagnetic Spectrum

The complete range of electromagnetic radiation arranged by wavelength and frequency.

Relationship Between Wavelength and Energy

Shorter wavelength means higher energy.