Chapter 11: Waves 1 Flashcards
What is a progressive wave?
A progressive wave is a type of wave where the oscillation travels through matter (or sometimes a vacuum) and carries energy but not matter.
What is displacement in waves?
Displacement in waves is defined as the distance of a point on a wave from the equilibrium position in a given direction.
What is amplitude?
Amplitude is the maximum displacement of a point on a wave from the equilibrium position.
What is time period and frequency?
Time period is the time taken for one complete wavelength to pass a point per unit time.
Frequency is the number of complete wavelengths that pass a point per given time.
What are longitudinal and transverse waves?
Longitudinal Waves are waves where the oscillation is parallel to the direction of energy transfer, whilst Transverse Waves are waves where the oscillation is perpendicular to the direction of energy transfer.
What are some similarities and differences between the two types of waves:
Similarities:
- They are both progressive waves.
- They both transfer energy but not matter.
Differences:
- Oscillations are parallel to direction of energy transfer in longitudinal whilst perpendicular in transverse waves.
- Transverse has peaks and throughs whilst longitudinal has compressions and rare factions.
What is the wave equation that links wavespeed, wavelength and frequency?
The equation that links wavespeed, wavelength and frequency is:
v = fλ
Wavespeed = Frequency x Wavelength
What is the equation for frequency when given time period?
When given time period:
Frequency = 1 / Time, f = 1 / t
What is Phase Difference?
Phase difference is the difference in displacement between particles on a wave or different waves, measured in radians or degrees.
Antiphase is when two points on a wave are completely out of phase, where one point reaches maximum displacement whilst the other point reaches maximum negative displacement.
What is reflection?
Reflection is the change in direction of a wave at a boundary between two different media, remaining in the original medium.
What is the law of reflection?
The law of reflection states that when waves are reflected, the angle of incidence is equal to the angle of reflection.
What is refraction?
Refraction is the change in direction of a wave due to a change in speed as it passes from one medium to another.
When this happens, the wave refracts towards the normal (if it is slowing down).
What is diffraction, and what is it dependant on?
Diffraction is the spreading out of waves as it passes through a gap in an obstacle.
Diffraction is dependant on the size of the gap, with a smaller gap creating a larger diffraction. The closer the gap is to the wavelength, the greater the spread.
What is polarisation?
Polarisation is where particles or matter in a transverse wave oscillate along a single plane. This can be done using a polarizing filter.
What is intensity, and its equation?
Intensity is defined as the radiant power passing through a surface per unit area. The equation for intensity is: I = P / A , Intensity = Power / Area OR I = P / 4πr^2
