3.3.1.3 Principle of superposition of waves and formation of stationary waves Flashcards
(16 cards)
What is a stationary wave
A wave formed by the superposition of two waves of the same frequency travelling in opposite directions
What is a node
A point on a stationary wave where there is zero amplitude at all times due to destructive interference
What is an antinode
A point on a stationary wave where the amplitude is maximum due to constructive interference
How are stationary waves formed
By two waves of the same frequency and amplitude travelling in opposite directions interfering
Give an example of where stationary waves form
A string fixed at both ends or a column of air or a microwave cavity
What does the equation f = 1 over 2l root T over mu calculate
The frequency of the first harmonic of a stretched string
What does l represent in f = 1 over 2l root T over mu
Length of the vibrating part of the string
What does T represent in f = 1 over 2l root T over mu
Tension in the string in newtons
What does mu represent in f = 1 over 2l root T over mu
Mass per unit length of the string in kg per metre
Where do nodes form on a vibrating string
At fixed ends and points of complete destructive interference
Where do antinodes form on a vibrating string
At points of maximum displacement between nodes
How many nodes and antinodes are present in the first harmonic
Two nodes and one antinode
What is meant by the first harmonic
The lowest frequency at which a stationary wave is formed on a string
Do stationary waves transfer energy
No energy is transferred by stationary waves
How are stationary waves formed in a microwave oven
By reflection and superposition of microwaves forming nodes and antinodes
How can stationary waves be demonstrated with sound waves
Using a loudspeaker and a tube closed at one end and moving a microphone to detect nodes
