4- Oscillations and Waves Flashcards
Energy SHM
1/2mω^2x
Refractive index
Speed of wave in medium 1 ÷ speed in medium 2
Red light wavelength
700 nanometres
Blue light wavelength
500 nanometres
Radio Micro Infrared Visible UV X Gamma
Electromagnetic spectrum
Simple harmonic motion
Motion where the acceleration of an object is directed towards a fixed point and is proportional to its displacement from that point.
Simple harmonic motion (equation)
a = −w^2x
Critically damped
Damping causes SHM to rapidly die away in the minimum time without completing an oscillation (like immersing in honey)
Longitudinal travelling wave
Direction of oscillation of particles is in direction of energy propagation
Amplitude (definition)
Maximum displacement from the mean
Angular frequency (equation)
ω=2π/T
Compressions
Points on a longitudinal wave where the particles are ‘bunched together’
Constructive interference
When two identical waves meet at a point and the waves are exactly in phase, the resulting wave has twice the amplitude of either of the original waves
Crest
The peak of a transverse wave (the point of maximum positive displacement)
Damping
Involves a force that is always in the opposite direction to the direction of motion of the oscillating particle and is a dissipative force (i.e. the oscillating particle loses energy)
Destructive interference
When two identical waves meet at a point and the waves are exactly (180°) out of phase, the resulting wave has zero amplitude – the two waves cancel each other
Gamma rays
10^-15 - 10^-10 m
Diffraction
The spreading of a wave past an aperture or obstacle.
For this to be observable, the size of the obstacle or gap needs to be the same order of magnitude as the wavelength
X-rays
10^-10 - 10^-8 m
UV
10^-8 - 10^-7 m
Visible
400 nm - 700 nm
Infrared
10^-6 - 10^-3 m
Microwave
10^-3 - 10 m
Radio
10 - 10^5 m
Frequency
Number of completed oscillations in a given period of time
Intensity (definition)
The power per unit area of a wave that is received by the observer.
Intensity (equation)
I = p/A
