Glossary
Beat frequency
The absolute difference between the frequencies of two interfering waves, which determines the rate at which the amplitude fluctuates.
Example:
If two tuning forks produce frequencies of 440 Hz and 442 Hz, the beat frequency heard will be 2 Hz, meaning two amplitude fluctuations per second.
Beats
The periodic variation in amplitude that results from the superposition of two waves with slightly different frequencies.
Example:
When a guitar string is slightly out of tune with a tuning fork, you can hear beats as the sound gets periodically louder and softer.
Constructive interference
Occurs when two or more waves combine in phase (displacements in the same direction), leading to an increase in the amplitude of the resultant wave.
Example:
When two speakers playing the same note are placed at specific distances, their sound waves can combine to create a louder sound in certain spots due to constructive interference.
Destructive interference
Occurs when two or more waves combine out of phase (displacements in opposite directions), leading to a decrease or cancellation of the amplitude of the resultant wave.
Example:
Noise-canceling headphones work by generating a sound wave that undergoes destructive interference with incoming ambient noise, effectively canceling it out.
Pass through each other
A unique characteristic of waves, unlike particles, where they continue their propagation after interacting, rather than colliding and bouncing off.
Example:
When two light beams cross in a dark room, they don't block each other but rather pass through each other, continuing their paths undisturbed.
Principle of superposition
A fundamental principle stating that when multiple waves overlap, the net displacement at any point is the vector sum of the individual displacements of each wave.
Example:
If a sound wave from a speaker and an echo from a wall meet, the total sound pressure at a point is found by applying the principle of superposition to their individual pressures.
Wave interference
The phenomenon that occurs when two or more waves interact and overlap, combining their amplitudes to form a resultant wave.
Example:
When ripples from two dropped pebbles meet in a pond, they create a complex pattern of combined waves, demonstrating wave interference.