Unit 2 Flashcards
Wavelength=
2L/n
Wave speed
Frequency . Wavelength
Frequency=
1/T
Transverse waves propagate
Up and down
Longitudinal waves propogate
To and fro
At what do transverse waves occur to their direction
At right angles
What are longitudinal waves to the direction
Parallel
Define amplitude
Max displacement from the equilibrium position
Define progressive waves
Waves that propagate/are in motion
Define stationary waves
Positions of peaks and troughs aren’t moving/are stationary
An example of a stationary wave
Plucking guitar strings
What is the amplitude at a node
Zero
What is the amplitude at an antinode
Maximum
Define superposition
When 2+ waves meet and their total displacement at any point is the sum of the displacements that each individual wave would cause at that point
What are waves that oscillate one wavelength apart
In phase
What are waves that oscillate 1/2 a wavelength apart
In anti phase
Draw a phase change of 180 degrees
Blimp travelling towards a wall then it reflects and is opposite on the way back from the wall (see notes if need be)
What would happen if a light ray travels from a less dense medium to a more dense medium? And with what phase difference?
It will reflect with a phase difference of 180degrees
What would happen if a light ray was travelling from a more dense medium to a less dense medium? And with what phase change?
It will not leave the more dense medium, just reflect internally with no phase change
Define what is meant by decay in terms of waves
Rate that amplitude decreases
What does the amount of diffraction depend on
The size of the gap and wavelength
How is max diffraction achieved
When the size of the gap equals the wavelength
Define total internal reflection
When the angle of reflection exceeds the critical angle
Define the critical angle
Angle of incidence when the reflected angle is 90degrees
What happens to the ray of light if the critical angle is exceeded
Total internal reflection is achieved
Define transmitted
When some of the wave passes across the barrier whilst the rest reflects
Define diffraction
Interaction between solid objects and waves
Refractive index=
Sini/sinr
What happens to the speed of a light ray when going from a more dense medium to a less dense medium
Slows down
What happens to The speed of a light ray when going from a more dense medium to a less dense medium
It speeds up
What does snells law say
That sini/sinr=a constant
Define refraction
Change of direction of a wave when it’s speed changes
Define reflection
When a wave hits a barrier and changes direction
Refractive index (from medium 1 to medium 2)
V1/V2
