Two fire alarms are placed in a building, one 3 m north of the other. A person sitting at a desk which is 52.6 m east and 5.2 m north of the point mid-way between the alarms does not hear them when they sound. a) What is the lowest frequency that the alarms can be sounding at, assuming that the alarms are both perfectly in phase? b) Are such "dead zones" (locations where the fire alarms are inaudible) likely to occur?
Properties of sound
A sound wave is a mechanical wave (or mechanical vibration) that transit through media such as gas (air), liquid (water), and solid (wood).
Quality Of Sound
A sound or a sound wave is defined as the energy produced due to the vibrations of particles in a medium. When any medium produces a disturbance or vibrations, it causes a movement in the air particles which produces sound waves. Molecules in the air vibrate about a certain average position and create compressions and rarefactions. This is called pitch which is defined as the frequency of sound. The frequency is defined as the number of oscillations in pressure per second.
Categories of Sound Wave
People perceive sound in different ways, like a medico student takes sound as vibration produced by objects reaching the human eardrum. A physicist perceives sound as vibration produced by an object, which produces disturbances in nearby air molecules that travel further. Both of them describe it as vibration generated by an object, the difference is one talks about how it is received and other deals with how it travels and propagates across various mediums.
Two fire alarms are placed in a building, one 3 m north of the other. A person sitting at a desk which is 52.6 m east and 5.2 m north of the point mid-way between the alarms does not hear them when they sound.
a) What is the lowest frequency that the alarms can be sounding at, assuming that the alarms are both perfectly in phase?
b) Are such "dead zones" (locations where the fire alarms are inaudible) likely to occur?
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