4.2 Measuring waves Flashcards
What happens when we make a phone call
Sound waves are converted to electrical waves
What happens in an intercontinental phone call
Sound waves are converted to electrical waves. These waves are carried by electromagnetic waves from ground transmitters to satellites n space and back to ground receivers, where they are converted back to electrical waves then back to sound waves.
What is the displacement of a vibrating particle
Its distance and direction from its equilibrium position
What is the amplitude of a wave
The maximum displacement of a vibrating particle.
For a transverse wave, this is the height of a wave crest or the depth of a wave trough from its equilibrium position
What is the wavelength of a wave
The least distance between two adjacent vibrating particles with the same displacement and velocity at the same time
What is one complete cycle of a wave
From maximum displacement to the next maximum displacement
What is the period of a wave
The time for one complete wave to pass a fixed point
What is the frequency of a wave
The number of cycles of vibration of a particle per second. The unit of frequency is the hertz (Hz)
The higher the frequency of a wave, the shorter its…
…wavelength
For waves of frequency f, the period of a wave =
T=1/F
Wave speed c =
fλ
What is the phase of a vibrating particle at a certain time
The fraction of a cycle it has completed since the start of the cycle
What is the phase difference between two particles vibrating at the same frequency
The fraction of a cycle between the vibrations of the two particles, measured either in degrees or radians where 1 cycle = 360°=2π radians
For two points at distance d apart along a wave of wavelength λ
The phase difference in radians = 2πd/λ
