Standing Waves by Jared Rovny, PhD

Name: Standing Waves
Uploaded: 2016-12-16
Duration: 12 min 10 s
Description: The lecture Standing Waves by Jared Rovny, PhD is from the course Sound.

About the Lecture

The lecture Standing Waves by Jared Rovny, PhD is from the course Sound.

Included Quiz Questions

What are the boundary conditions which a standing air pressure wave has to satisfy in a half open pipe ?

The open end must be fixed at atmospheric pressure but the pressure at the closed end can be at maximum or minimum amplitude
Both the open and closed end are fixed at atmospheric pressure
Both the open and closed end can be at maximum or minimum pressure
The open end is at minimum pressure but the closed end is at maximum pressure
The pressure at the open end can be at maximum or minimum pressure as there is flexibility for oscillation but the closed end is fixed at atmospheric pressure as there is no flexibility for change

Why can the pressure in a pipe be maximized or minimized at the closed end of the pipe but not the open end ?

Air cannot move past the closed end and equilibrate the pressure whereas in the open end this is possible
The wall pushes air molecules to the highest possible pressure but in the open end this is not possible
Air molecules bounce against the wall and cause more pressure
The wall produces a beat frequency with higher pressure
The closed end is in opposition to the open end, where the pressure is produced

Why is there a minimum frequency (lowest pitch) that can resonate in a pipe?

The boundary conditions at the ends of the pipe cannot be matched by sound waves that have longer wavelengths
The pipe cannot vibrate at lower frequencies, because of its limited size
Lower frequencies have very short wavelengths, which are too short to meet the end conditions of the pipe
Longer wavelengths will not be able to maximize or minimize the pressure at the closed or open ends of a pipe
Sound waves move too quickly to allow lower frequencies to stay in a pipe of finite length

What does the letter n represent in the equation for the allowed wavelengths of standing waves in a half open pipe: λ = 4L/(2n + 1) ?

n = 0, 1, 2, 3, …
n = 0, L, 2L, 3L, …
n = 1, 2, 3, ...
n = 1, 3, 5, ...
n = 0, 2, 4, ...

What is the formula for the allowed frequencies of standing waves in a half open pipe of length L ? The formula for the allowed wavelengths is λ = 4L/(2n + 1) and consider v as the speed of sound in air.