What does a progressive wave do
Carry energy from one place to another without transferring any material
What is displacement of a wave?
How far a point on a wave has moved from its undisturbed position
What is the period of a wave
Time taken for a whole cycle to pass a given point
What is the frequency of a wave
Number of cycles per second passing a given point
What is refraction of a wave
When the wave changes direction as it enters a different medium
Difference between how longitudinal and transverse waves oscillate
Transverse-perpendicular to direction of energy transfer
Longitudinal-parallel to direction of energy transfer
What is a polarised wave?
Transverse waves that only oscillates in one direction
Example of something that uses polarising filters to block out unwanted glare
Polaroid sunglasses
What is superposition?
When multiple waves pass through each other, the resultant wave is the vector sum of the individual displacements
What is constructive interference?
crest+crest or trough+trough (in phase) to form a bigger wave
What is destructive interference?
crest+trough of equal size, pi out of phase. Cancel each other out
How do 2 points in phase interfere (constructive or destructive)
Constructively
Phase difference of exactly out of phase points
Multiples of pi radians or 180 degrees
When are 2 sources coherent
Same wavelength, same frequency, fixed phase difference
Path difference for constructive interference
n x wavelength (where n is an integer)
Path difference for destructive interference
(n+0.5) x wavelength (n is an integer)
What is a standing/stationary wave?
The superposition of 2 progressive waves with the same frequency moving in opposite directions
Is energy transmitted by a stationary wave?
No
When are there nodes and anti-nodes in stationary waves
nodes- No amplitude
anti-nodes: At Amplitude
Meaning of the letters in f=1/2l(sqrt(T)/mu)
l= length of string in m
T= tension in the string
mu=mass per unit length of the string
What is wave diffraction?
The way waves spread out as they come through a narrow gap
When you get the most diffraction
When the gap is the same size as the wavelength
What does diffracting white light produce?
A spectra of colours
What effect does increasing the slit width have to intensity of the central maximum and why?
Decreased amount of diffraction, central maximum is narrow and intensity is higher
