What is light, EM Waves, Types of Light and Lasers

Properties of Light

1. Transverse Waves (move up and down)

2. Dont require medium to travel through (radiation)

3. Travel at speed of light in a vaccum (3.00 × 10^8 m/s)

4. Can be reflected or refracted

5. Travels in straight lines

What is light

An electromagnetic Wave

Electromagnetic wave

Wave w/ both electric and magnetic parts, doesn’t require medium so energy transferred by radiation

Wave

Disturbance that transfers energy from 1 point to another, w/o transferring matter

Medium

Any physical substance through which energy can be transferred

Radiation

Method of energy transfer that doesnt require medium, can travel through a vacuum (empty space)

Wavelength

Distance btwn 2 like-points on a wave

Amplitude

Height of wave compared to undisturbed state

Frequency

# of waves passing in given amount of time

Period

Amount of time required for 1 wavelength to pass

Types of Electromagnetic Wave (increasing energy order)

Radio - Microwave - Infrared - Visible - Ultraviolet - X Ray - Gamma Ray (shorter wavelengths)

Visible Light

Only part of EM spectrum that can be seen by human eye

• Colours distinguished by diif wavelengths of light, they are a spectrum

• White light includes: Red, Orange, yellow, green, blue, indigo, violet (in increasing energy order)

Luminous VS Nonluminous light

Luminous - emits own light in all directions

Non luminous - doesnt emit own light but can reflect it

Incandescent Light

Electric Discharge

Chemiluminescence

Triboluminescence

Phosphorescence

Fluorescence

Bioluminescence

Light Emitting Diode (LEDs)

Laser Characteristics

Pure in colour, Very Intense, Concentrated in 1 narrow beam

• Produces EM waves of same energy level, that travel in same direction and in exact unison