goals

Two identical sound waves each of loudness $$\beta$$ interfere constructively at a point to produce a sound level of

The analysis of the radiation pattern from a circular piston cab be carried out in the same way as that for a long rectangle. The piston is subdivided into narrow circular zones instead of long strips, and the effect of the waves from all the zones is summed at a distance point. There is a maximum of intensity along the axis of the piston, as would be expected. The angle $$a$$ at which the first minimum occurs is given by

$$\displaystyle \sin a = 1.22 \dfrac{\lambda}{D}$$

where $$D$$ is now the piston diameter . If $$D = 0.3\ m,\ \lambda = 0.15\ m$$.

$$\displaystyle \sin a = 1.22 \left(\dfrac{0.15m}{0.3m}\right) =0.61$$

$$\displaystyle a \approx 38$$

About 85 percent of the radiant energy is concentrated within a cone of this half angle, other minima and maxima of rapidly decreasing intensity surround the central maximum.

$$\displaystyle \sin a = 1.22 \dfrac{\lambda}{D}$$

where $$D$$ is now the piston diameter . If $$D = 0.3\ m,\ \lambda = 0.15\ m$$.

$$\displaystyle \sin a = 1.22 \left(\dfrac{0.15m}{0.3m}\right) =0.61$$

$$\displaystyle a \approx 38$$

About 85 percent of the radiant energy is concentrated within a cone of this half angle, other minima and maxima of rapidly decreasing intensity surround the central maximum.

When a sound wave enters the ear it sets the ear drum into oscillation, which in turn causes oscillation of the three tiny bones in the middle ear called the ossicles. This oscillation is finally transmitted to the fluid-filled inner ear. The motion of the fluid disturbs hair cells within the inner ear, which transmit never impluses to the brain with the information that a sound is present. The moving part of the eardrum has an area of about 43 $$m^2$$, and the area of the stirrup (The smallest of the ossicles) where it connects to the inner ear is about 3.2 $$m^2$$. A moderate loudness sound of maximum pressure variation are of the order of $$\displaystyle 3\times 10^{-2}$$Pa above and below atmospheric pressure of $$\displaystyle 10^5$$Pa.

In humans, the sound is produced by: