# Physics - Standing Waves

> Source: https://ollybritton.com/notes/a-level/physics/topics/standing-waves/ · Updated: 2021-06-17 · Tags: school, physics, year-1

## See Also
- [Physics - Waves](https://ollybritton.com/notes/a-level/physics/topics/waves/)

## Flashcards
##### When is a standing wave formed??
When two waves with the same frequency and amplitude travelling in opposite directions are superimposed.

##### What are the points of total constructive interference in a standing wave called??
Antinodes.

##### What are the points of total destructive interference in a standing wave called??
Nodes.

##### What is the seperation between adjacent nodes or antinodes in a standing wave??
$$
\frac{\lambda}{2}
$$

##### How much energy transfer is there in a standing wave??
None, since the waves making it are travelling in opposite directions.

##### How can you form a standing wave using microwaves??
Reflect microwaves from a microwave transmitter off a metal plate some multiple of the wavelength awy.

##### Why are waves closer to the metal plate better at creating total nodes in a microwave standing-wave experiment??
Because there is the smallest difference in distance travelled and therefore smallest difference in amplitude.

##### What is the phase difference for each point on the trough of a standing wave??
$$
0
$$

They are in phase.

##### What is the phase difference for each point on the peak of a standing wave??
$$
0
$$

They are in phase.

### 2021-07-01
##### What's another word for a standing wave??
A stationary wave.

##### ![PHOTO STATIONARY WAVE STRING](stationary-wave-string.png) Why does is a stationary wave formed when a taut string is plucked??
Because two progressive waves travel in opposite directions and reflect off the nodes.

##### ![PHOTO STATIONARY WAVE STRING](stationary-wave-string.png) What is the wavelength of the progressive wave formed by plucking this string??
$$
\lambda = 2L
$$

##### What is the fundamental mode of vibration of a string??
The simplest standing wave that can be formed by progressive waves travelling along the string.

##### What is the fundamental frequency of a string??
The frequency of the progressive wave that forms the simplest standing wave on a string.

##### What's the frequency of the 1st harmonic in terms of the fundamental frequency $f_0$??
$$
f_0
$$

##### What's the frequency of the 2st harmonic in terms of the fundamental frequency $f_0$??
$$
2f_0
$$

##### What's the frequency of the 5th harmonic in terms of the fundamental frequency $f_0$??
$$
5f_0
$$

##### Why is the speed of sound greater at night time??
The speed of sound is temperature dependent.

##### What is true about the speed of progressive waves along a string at fixed tension??
It is constant.

### 2021-09-19
##### When might the wavelength of the fundemental mode/first harmonic in a stationary wave be $\frac{\lambda}{4}$??
When the stationary wave is formed in a closed tube.

##### What two situations might mean the wavelength of the fundemental mode/first harmonic in a stationary wave is $\frac{\lambda}{2}$??
When the stationary wave is formed on a fixed string or an open tube.

##### What do you find at the ends of an open tube when forming a stationary wave??
Antinodes.

##### What is the formula for the fundamental mode of a string with length $L$, tension $T$ and mass per unit length $\mu$??
$$
f = \left\frac{1}{2L}\sqrt{\frac{T}{\mu}}\right
$$

### 2022-06-01
##### What are at both ends of a standing wave present on a string fixed at both ends??
Nodes.

##### What are at either ends of a standing wave present on a string fixed at one end??
* Fixed: Node
* Open: Antinode

##### What are at both ends of a standing wave present in an open pipe??
Antinodes.

##### What are at either ends of a standing wave present on a pipe with one closed end??
* Closed: Node
* Open: Antinode.

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