Chapter 11 Waves 1 & 2 Flashcards
Amplitude
Maximum displacement from the equilibrium position in a particular direction.
Displacement
Distance from the equilibrium position of a POINT in a particular direction. It is a vector so can have a negative value also.
Wavelength
Minimum distance between two points in phase on adjacent waves.
Frequency
The number of wavelengths passing a given point per unit of time.
Period
Time taken to complete 1 wave.
Wave equation
Velocity = frequency x wavelength
Wave speed
Distance travelled by the wave per unit time.
Phase difference
Difference in displacements in particles on a wave
Progressive wave
A progressive wave is a wave that can travel through matter or through a vacuum and carries energy from one place to another.
Longitudinal wave
Waves that travel through a medium and create rarefactions and oscillations and oscillate parallel to the direction of motion.
Transverse wave
A transverse wave oscillates perpendicular to the direction of travel.
Examples of transverse waves
All electromagnetic waves
s waves in earthquakes
Examples of longitudinal waves
P waves from an earthquake
sound waves
What is it called when two particles are oscillating 180 degrees out of phase?
Antiphase
What is Refraction?
Refraction is when a wave passes through a more/less optically dense medium and changes wave speed, bending the waves either towards or away from the normal depending on the density of the material it is entering.
What is reflection?
Reflection is when a wave changes direction at a boundary between two different mediums, remaining in the original medium.
What is the law of reflection?
Angle of incidence = Angle of reflection
Where is the angle of incidence measured from?
It is measured from the normal.
How do you calculate the refractive index of a material?
n = Speed of light in a vacuum/speed of light in the solid
or snells law N1 sin theta1 = N2 sin theta2
What are the conditions needed for total internal reflection to occur?
The wave needs to be going from a more to a less dense medium
The wave needs to have an angle of incidence greater than its critical angle