Chapter 24, Problem 4Q

To determine

To explain: “Sounds can hear around corners, it cannot see around corner” should be explained.

Answer to Problem 4Q

Because of diffraction and reflection, a person can hear sounds around corners, but not see around corners.

Explanation of Solution

Introduction: Diffraction effect is noticeable once a size of any object that a wave is diffracting around is same size as the wavelength of wave. Angle of reflection is equals to angle of incidence. The law of reflection applies to both, totally reflected waves and partially reflected.

Sound waves have long wavelengths as compared to the light waves. This makes diffraction properties much more noticeable. The wavelength of sound is $1m$ , whereas, the wavelength of light is $0.1\mu m$ .

Sounds waves reflects from walls so well in specular manner. Therefore, it can bounce around the corners, but light reflects from the walls in diffuse manner. So, another reason for certain is reflection.

Conclusion: Diffraction and reflection can change the hearable tendency of sound.