3.1 Progressive and stationary waves Flashcards
Define amplitude.
Maximum displacement of the wave from its equilibrium position.
Define frequency.
The number of wave cycles passing through a point per second.
Define Wavelength.
The distance between two idential points on a wave.
e.g. two adjacent troughs/peaks on a wave.
Define time period.
The time to complete one wave cycle.
What is the equation for wave speed?
What is the equation linking frequency and time period?
What do the letters represent in this equation?
Define phase.
Position of a certain point on a wave cycle.
What is phase difference?
How much a wave lags behind another wave.
Measured as angles (radians and degrees) or fractions of a cycle
What is a progressive wave?
Waves that carry energy between points.
What is a longitudinal wave?
Direction of vibration of the particles/fields is parallel to the direction of energy propagation
What is a transverse wave?
Direction of vibration of the particles/fields is perpendicular to the direction of energy propagation
What type of wave is a sound wave?
Longitudinal
What type of wave is a electromagnetic wave?
Transverse
What does it mean for a wave to be polarised?
The wave oscillates only in one direction.
How is polarisation used as evidence of the nature of transverse waves?
Polarisation can only occur if a wave’s oscillations are perpendicular to the direction of motion
How does a polarisation filter work?
Blocks all oscillations not parallel to the filter’s transmission axis.
What is the principle of superposition?
When two waves meet, the total displacement at a point is equal to the sum of the individual displacements at that point.
What is a stationary wave?
A wave which transfers no energy and whose positions of maximum and minimum amplitude are constant.
What is constructive interference?
When two waves meet and are in phase.
What is destructive interference?
When two waves meet and are 180o out of phase
What are nodes?
A point on a stationary wave where the displacement is 0.
Point of destructive interference
What are antinodes?
A point on a stationary wave with maximum displacement.
Point of constructive interference
What is the distance between adjacent nodes?
Half a wavelength
Same for adjacent antinodes
How are stationary waves formed?
- The waves must be of the same frequency, wavelength and amplitude.
- They must be travelling in opposite directions.
What is the equation for the first harmonic?
What do the letters represent in this equation?
What is the nth harmonic?
n times the first harmonic
What do the letters represent in this equation?
