Waves Flashcards
State four wave phenomena that can apply to EM and sound waves.
Refraction
Reflection
Diffraction
Interference
Describe how to observe the polarisation of microwaves.
Place a transmitter and receiver facing each other.
Place two polarising filters in the middle and rotate one of them.
Observe the signal changing from zero to a maximum reading.
Suggest the apparatus you would use to detect and measure the frequency of sound waves.
Microphone -> mechanical motion into electrical signals
Oscilloscope -> displays oscillations
Define node
A point on a standing wave where the displacement is zero.
Define antinode
A point on a standing wave where the displacement is at its maximum.
Explain how a progressive wave on a string can form a stationary wave.
Progressive wave travels along the string and is reflected at the end of the ‘wire’.
The incident wave and reflected wave interfere.
Points of destructive interference produces nodes and points of constructive interference produces antinodes.
Explain why a pattern is produced when electrons travel through graphite.
Electrons have a wavelength.
Gaps between C atoms are roughly the same size as the wavelength of electrons so diffraction takes place
Constructive interference takes place and pattern is seen.
Define wavelength
The distance between two consecutive points with the same phase on a wave.
Define frequency
The number of wavelengths passing through a point per unit time
Define speed
The distance a wave travels per unit time
Define amplitude
Maximum displacement from equilibrium
State the principle of the superposition of waves.
When two or more waves meet, the resultant displacement is equal to the sum of the displacements of each wave.
