Optics Unit Test Flashcards
What’s a wave
A disturbance that transfers energy from one point to another without transferring matter
Crest
Highest point in a wave
Trough
Lowest point in a wave
Wavelength
the distance from one place in a wave to the next similar place on the wave
Amplitude
the wave height from the rest position of the wave to the crest or the wave depth from the rest position to the trough
Frequency
the rate of repetition of a wave
As frequency increases
the wavelength decreasss
As frequency decreases
the wavelength increases
Drawing a Wave
- Make a rest position depending on the amplitude
- Mark how long the wavelength is
- Mark the middle of the wavelength
- Mark the middle of that wavelength, creating half
- Mark the crest depending on the amplitude
- Mark the trough depending on the amplitude
- Draw the wavelength and label everything
Speed Over Wave is…
V = λ x f
the triangle!
V
f λ
v = f x λ f = v/λ λ = v/f
Light is an…
electromagnetic wave
Electromagnetic Radiation
Wave pattern made of electric and magnetic fields that can travel through empty space (sound isn’t electromagnetic!)
Electromagnetic Spectrum
Range of electromagnetic radiation arranged from shortest (gamma rays) to longest (radio waves)
- The wavelength (and therefore the frequency) of a light wave will depend on the scale of the disturbance in the EM fields
Order of the Electromagnetic Spectrum
- Radio Waves
- Microwaves
- Infrared Waves
- Visible Light
- Ultraviolet rays
- X-rays
- Gamma Rays
Radio waves
The longest wavelength and lowest frequency waves. Used to transmit television signals and important for many forms of communication
Microwaves
Shorter wavelengths than radio waves. Used in cell phones, radio, and cooking food.
Infrared waves
Have shorter wavelengths than microwaves but longer wavelengths than visible light. Used to detect the formation of new stars in nebulas due to the heat they give off.
Visible light
The part of the spectrum that human eyes can visibly detect. Red light has the longest λ, ~700 nm. Violet light has the shortest λ, ~400 nm.
Ultraviolet rays
Have shorter wavelengths than visible light. Can be used to create sterile environments and treat jaundice in babies, too much can cause sunburn
X-rays
Very high energy radiation, penetrate human tissue. Used in medical practices to see internal structures, used to study black holes
Gamma rays
Extremely high energy radiation, penetrate human tissue. Used to target and kill cancer cells, study black holes.
White light is composed of…
Different colour wavelengths of visible light
Primary colours
red, blue, green (RBG)
Blue + Red = Magenta
Blue + Green = Cyan
Red + Green = Yellow
Secondary Colours
magenta, cyan, yellow
Mix two equal amounts of primary to make secondary
When mixed correct amount of all the primary colours you will make…
white light
Blue + Green + Red = White
When mixing a primary with a secondary you will make…
white
Green + Magenta = White
Blue + Yellow = White
Red + Cyan = White
Primary Colours (subtractive)
Magenta, Yellow, Cyan
When a lightwave strikes an object, some wavelengths of light will…
reflect
The colour you see when you look at an object depends on the…
Wavelengths that are reflected
Coloured matter selectively…different colours or wavelengths of light and the colours that are absorbed are…from the reflected like that is seen
- absorbs
- retracted
Primary and secondary colours of light for the subtracted theory are…to the colours of the additive theory
- opposite
Magenta + Cyan = Blue
Cyan + Yellow = Green
Yellow + Magenta = Red
When all three subtractive primary colours are mixed they make…
black
When a colour is absorbed…
You will only see…
- it will not make it to your eye
- reflected colours
Primary Reflected/Absorbed
In blue objects: blue reflected, red green absorbed
In red objects: red reflected, green red absorbed
In green objected: green reflected, blue red absorbed