The wavelength of a sound can be found by utilizing the equation, . where v is the velocity of sound,  is the wavelength, and f is the frequency. You should know that sound normally travels with a speed of 340m/s, unless otherwise stated. With the information given we can find the wavelength of the traveling sound to be 0.11m.

First, notice that the paragraph above tells us that the wave can be modeled as a pipe with one end closed. This is in contrast to the other possibility, where the wave is modeled as a pipe with two ends open. It is critical to recognize this difference, as the definition of sequential harmonics and the formula used to calculate them changes depending on whether both ends are open or not. In the situation where one end is closed, the harmonics are odd numbers, meaning that the first three harmonics are 1^st, 3^rd, and 5^th. In the situation where both ends are open or both ends are closed, the harmonics are sequential, meaning that the first three harmonics are 1^st, 2^nd, and 3^rd.

The question asks us to determine how long it will take for a wave beat to reach an audience member at 100m away; thus, we need to calculate the velocity of the wave to determine the time.

We know from kinematics that . This can be rearranged to solve for t: .

This question asks us to incorporate information we learned in the pre-question text and new information in the question. First, we are told that we are looking to calculate a distance where maximal sound is heard, in other words, where the amplitude is at its maximum. This only occurs at an anti-node. 

Additionally, we know that the speaker can be modeled as a one-end closed pipe, meaning that the wavelengths of the harmonics are calculated as .

In a one-end closed pipe model, each harmonic ends with maximal amplitude, so we can find L (the length of the pipe, i.e. where the person standing would hear maximal sound), as we know the fundamental harmonic has n = 1.

This question asks us to determine the intensity of a wave, given to us as a comparison of the wave intensity to the intensity of the limit of human hearing. In math terms, we know that the decibel scale is calculated as shown below.

I₀ is the limit of human hearing (10^-12 W/m²).

A simple definition of a standing wave is a wave that is self-reinforcing, which is to say that reflection of the wave through the medium results in some areas of amplification (anti-nodes) of the wave and some areas of nullification (nodes). In other words, resonance must occur, and that usually suggests confinement of the wave in some fashion.

A fan and a bus make noise and vibration, but the sound does not resonate. It is transmitted, but not confined. Light with a specific wavelength has no "resonant" character, and neither do waves striking a pier. If the waves were confined in a harbor so that they could amplify, it might be possible to produce a standing wave. Microwaves trapped inside a microwave oven have this feature, producing antinodes of intense heating and nodes where no energy is transmitted into the food; this is the reason that microwave ovens have rotating platforms to make heating of the food item more uniform.

A violin string will be seen to have discrete, stable regions of motion and lack of motion, the requirements of the standing wave phenomenon. The points of reflection on the string are the two ends. The vibration of the wave is confined within the string, amplifying the sound as the nodes overlap.

In an open-closed pipe, we get only odd harmonics, since there must always be a displacement node at the closed end and a displacement antinode at the open end. So, the first overtone is the same as the third harmonic, which has . Similarly, the second overtone is the fifth harmonic, which has . Using the given value of  in the first overtone to be 300Hz, we find  and .

The bright lines from a diffraction grating can be located with the equation , where  is wavelength, d is the distance between slits in the diffraction grating, and  is the angle of separation from the center of the interference pattern on the screen.   is proportional to , so if  decreases, the angle of separation between lines also decreases.

Polarization is the property that allows tansverse waves to oscillate in multiple orientations. A transverse wave can oscillate, for example, in either the xy-plane or the yz-plane.

Sound waves are longitudinal, and thus do no experience polarization as medium is displaced in one direction only. A longitudinal wave will travel in only one dimension via compression and rarefraction.

The angle of reflection is the angle between the reflected light ray and a line perpendicular to the interface between the two media. The angle of reflection must be complementary to 20^o.

90^o – 20^o = 70⁰