5. Stationary Waves

Question 1

What is a Stationary Wave?

Answer 1

A Stationary Wave is the Superposition of two progressive waves with the same frequency (or wavelength) and amplitude, moving in opposite directions.

Question 2

What is the difference between a Stationary Wave and a Progressive Wave?

Answer 2

Unlike a Progressive Wave, Stationary Waves transmit no energy due to the fact that the energy of one wave cancels out the energy of the other.

Question 3

What is a Node?

Answer 3

A node is a point on a stationary wave where the amplitude is at zero.

Question 4

What is an Antinode?

Answer 4

An Antinode is a point on a stationary wave where the amplitude is at a maximum

Question 5

What is a Resonant Frequency?

Answer 5

The resonant frequency is the only frequency at which a stationary wave can be formed, and there are multiple harmonics which they take up, i.e. First Harmonic, … x Harmonic.

Question 6

What is the First Harmonic?

Answer 6

The First Harmonic is where the Stationary wave is vibrating at its lowest possible resonant frequency, it has one “loop” with a node at each end. The wavelength of a wave in the first harmonic would be double the length of the string it was formed on.

Question 7

What is the Second Harmonic?

Answer 7

The Second Harmonic has twice the frequency of the first harmonic, there are two “loops” with a node in the middle and one at each end, the wavelength of a wave in the second harmonic is equal to the length of the string it was formed on.

Question 8

What is the Third Harmonic?

Answer 8

The Third Harmonic has three times the frequency of the first harmonic, and has a wavelength equal to 2/3s the length of the string.