Waves Flashcards
Transverse waves oscillate
Perpendicular to direction of energy transfer of the wave
Longitudinal waves oscillate
In straight lines
Wave speed equation
Velocity = wavelength x frequency
Refraction is
When light bends when it hits a different medium
When light enters a more optically dense material it will
It slows down
It bends closer to the normal
The angle of refraction is smaller than the angle of incidence
When light enters a less optically dense material it will
It speeds up
It bends further from the normal
The angle of refraction so larger than the angle of incidence
What is the angle of incidence
The angle between the incident light ray and the normal
The normal is a line at 90 degrees to the plane
What is the Angle of reflection
The angle of reflection is the angle between the reflected light ray and the normal
Law of reflection
The angle of incidence = the angle of reflection
Sound waves
Longitudinal waves
Are produced by the vibration of particles in a medium
Travel in a series of compressions and rarefactions
Uses of sound waves
Ultrasound
Water depth
Medicine
Training dogs
Industry
Earthquakes
P - waves
Longitudinal , seismic waves
Travel at different speeds through solids and liquids
Earthquakes s-waves
Transverse , seismic waves
Cannot travel through liquids only solids
Em waves are all
Transverse waves that travel at the same speed or velocity in a vacuum
Wavelength vs frequency in em waves
As you move from gamma to radio waves , the wavelengths increase and the frequency decreases
Radio waves have the longest wavelength and lowest frequency
Gamma rays have the shortest wavelength and highest frequency
Em waves in order
From low to high frequency
Radio waves , microwaves , infrared , visible light , ultraviolet, x-rays , and gamma rays
How do lenses form an image
By refracting light
They can either be concave or convex
Convex lens
Curved on both sides and is wider at the middle than edges
Place where all light rays meet is parallel to the axis meet
The distance form the lens to the principle focus is the focal length
They are also known as converging lens
Images produced are virtual or real
Concave lens
Wider at the edges than in
the middle
When parallel rays of light enter a concave lens they disperse (spread out)
If you trace back along the paths of dispersed rays they will look like they came from the principal focus that is behind the lens
They are also known as a diverging lens
Images produced are only virtual
Radiation and surface colour
Black surfaces
Good absorbers
Good emitters
Poor reflectors
Radiation and surface colour
Shiny
Poor absorbers
Poor emitters
Better reflectors than dull of the same colour
Radiation and surface colour
White
Good reflectors
Poor emitters
Poor absorbers
A perfect black body
An object that absorbs all the radiation incident on it
Does not reflect or transmit any radiation
Would also be the best possible emitter as a good absorber is a good emitter
Optimal conditions for the fastest emitting of radiation
High surface area
High surface temperature
Uses and properties of gamma rays
Medical imagery
Astronomy
Sterilisation
Food preservation
They are very penetrating and damaging to living tissues and cells
Uses and properties of X-rays
Highly ionising so can damage body cells
They penetrate soft materials
Low energy - medical and industrial imagery
High energy - treat cancer
Security purposes
Uses and properties of uv light
Medical and forensic photography , air purification , disinfection and medical therapy , detect fake bank notes
Too much exposure can cause skin burns , skin cancer and cataract formations in the eye
Uses and properties of infrared radiation
Tv controls
Security purpose
Can cause serious skin burns if emitted from high intensity sources
Uses and properties of microwaves
Satellite communications , cooking food , transmit signals
Can be harmful to humans
Uses and properties of radio waves
Radio and TV communications
Can cause internal heating of a living tissue with potentially harmful effects
Visible Light
ROY G BIV
See the world and fibre in optics
red , orange , yellow , green , blue , indigo and violet
Amplitude is
The distance from the peak to equilibrium point
Rarefaction is
The area of a longitudinal wave that is more spread out
Compression is
The area of a longitudinal wave that is close together
