Waves Flashcards
What is a wave
Mean of transferring energy and information from one point to another without the transfer of matter
What is amplitude
Maximum displacement of particles from their resting or equilibrium position
Height of crest or depth of trough
What is wavelangth
Distance between a particular point on a wave and the same point on another wave
What is frequency and what is it measured in?
Number of oscillations in one second
Measured in hertz (hz)
What is the equation for time period
Time period= 1/ frequency
What is the wave equation
Wave speed (m/s)= Frequency (hz) * Wavelength (m)
What are transverse waves
When the direction of vibrations are perpendicular to the direction of the waves
What are longitudinal waves
When the direction of vibrations are parallel to the direction of the waves
What is it called when the medium of a wave is close together
Compression
What is it called when the medium of a wave is far apart
Rarefaction
What are Wavefronts
Imaginary line that represents the vibrating part of a wave
Displacements at any points are the crests of the wave
Name the parts of the electromagnetic spectrum from the longest to the smallest
Radio waves, Microwaves, Infrared, Visible, Ultraviolet, X-ray, Gamma
What are common properties of the electromagnetic spectrum
Transfer of energy and information
All are transverse waves
Travel at the same speed through a vacuum
Can be refracted, reflected, diffracted and interfered
Harms of Electromagnetic spectrum
Gamma: Cell mutation/cancer
X-rays: Cell mutation/cancer
Ultraviolet: Skin cancer/sunburn
Infrared waves: Skin burn
Microwaves: Internal heating of body tissues
Uses of Electromagnetic spectrum
Gamma: sterilize medical tools to kill bacteria
X-rays: photograph bones
Ultraviolet: detecting security ink
Infrared: optical fibre communications
Visible: seeing and photography
Microwaves: satellite communication
Radio: long range communication
Name the parts of the electromagnetic spectrum from the longest to the smallest
Radio waves, Microwaves, Infrared, Visible, Ultraviolet, X-ray, Gamma
Name the parts of the electromagnetic spectrum from the longest to the smallest
Radio waves, Microwaves, Infrared, Visible, Ultraviolet, X-ray, Gamma
What is the law of reflection
Angle of incidence (i) = Angle of refraction (r)
What are Virtual images and eg
They are formed only where light rays appear to come from
It cannot be formed by a screen
Images in mirrors are virtual
What is Refraction
What happens when light enters a denser medium
What happens when light enters a less dense medium
Refraction is the change in direction of a wave due to changes in speed as the wave passes from one medium to another
Denser medium: Speed decreases, light changes direction towards the normal, angle of refraction is less than angle of incidence
Less dense: Speed increases, light changes direction away the normal, angle of refraction is greater than angle of incidence
What is the refractive index and what are its equations
Measure of how much a wave changes direction when it enters a new medium
N= sin(i) / sin(r)– less dense to more dense
1/N= sin(i) / sin(r)- more dense to less dense
What is the critical angle and its equation
Angle of incidence that results in a angle of refraction of 90
Sin(c)= 1/n
What is TIR, when does it occur, and what are 3 uses of it
Total Internal Reflection, It is the complete reflection (no refraction) of light on a boundary between more to less dense object. i >c
Uses include Prismatic periscope, Reflectors and optical fibre communication
What is dispersion
When a prism splits the colours of white light into the spectrum
It occurs because the refractive index varies with the colours of white light
