waves Flashcards
What are waves?
Waves are a phenomenon in which energy is transferred through vibrations carrying energy away from a source
Define transverse waves.
Waves that travel in a direction perpendicular to the direction of the vibrations.
Define longitudinal waves.
Longitudinal waves are waves that travel in a direction parallel to the direction of the vibrations.
Define crests and troughs.
Highest and lowest points of a transverse wave, respectively. For longitudinal waves, the terms compressions and rarefactions are used
What is phase?
Any two points moving in the same direction and have the same speed and the same displacement from the rest position are said to be in phase. Any two crests or troughs are always in phase.
Define wavefront.
An imaginary line that joins all points on a wave that are in phase
Define wavelength.
The shortest distance between any two points in a wave that are in phase (e.g. two successive crests or troughs)
Define amplitude.
Maximum displacement from the rest or centre position
Define frequency.
Frequency is the number of complete waves generated per second. It is also the number of crests or troughs that pass a point per second.
Define period.
Period is the time taken to generate one complete wave. It is also the time taken for any given point on the wave to move a distance of one wavelength.
What is the speed of a electromagnetic wave?
3 x 10^8 m s^-1
What are the electromagnetic waves? (Hint: Ronald Mcdonald)
Radio waves, Microwaves, Infrared waves, Visible light, Ultraviolet rays, X-rays, Gamma rays
How is frequency and period related?
f = 1/T, f = frequency (Hz), T = period (s)
speed of wave =
v (m/s) = f (Hz) x lambda (m)
