Question

Why is the diffraction of sound waves more evident in daily experience than that of lightwave?

Answer 1

The reason for the diffraction of sound waves being more evident in daily experience than light waves is that sound waves have much higher wavelength compared to the visible light waves. For diffraction to occur, the slit width should be comparable to the wavelength of the light or sound waves. This condition is satisfied only for sound waves in everyday life. Thus sound diffraction is prominent.

Complete Step by step solution:
The wavelength of sound waves is much higher than that of visible light. The frequency of human audible sound waves lies from $20\;Hz$ to $20\;kHz$. The wavelength of sound generally ranges from $17\;m$ to $15\;mm$. The general wavelength of visible light ranges from $7000 \times {10^{ - 10}}m$ to $4000 \times {10^{ - 10}}m$. Sound travels by longitudinal waves which radiate outward in concentric circles. The motion of vibration in longitudinal waves is in the same direction as the wave propagation. This does not happen in electromagnetic waves.
For observing the phenomenon of diffraction, the order of the magnitude of the wavelength of the waves should be comparable to that of the slit width. Therefore to encounter diffraction on electromagnetic waves in our normal lives, we would require microwaves and not visible light since microwaves have a much higher wavelength and the longer wavelengths of about $3\;cm$ can be seen in low light conditions.

Note: Diffraction refers to the phenomenon of a wave encountering an opening or obstacle. The wave then bends around the corners of an obstacle, through apertures into the regions of the shadow of the obstacle. The aperture or the diffracting object effectively then becomes the second source of the wave.