Explain the following: (a) In a sound wave, the displacement node is a pressure antinode and vice versa (b) Bats can ascertain distance, direction, nature and sizes of the obstacles without any eyes. (c) Solids can support both longitudinal and transverse waves, but only longitudinal waves can properties in gases (d) The shape of a pulse gets distorted during propagation in a dispersive medium
(a) A sound wave decrease in displacement node cause an increase in the pressure there. Also an increase in displacement is due to the increase in pressure. (b) Bats emit ultrasonic waves of high frequency from their mouths. These waves after being reflected back from the obstacles on their path are observed by the bats. Using these waves’ bats can find the direction, distance, nature and size of the object. (c) This is due to the fact that gases have only the bulk modulus of elasticity whereas solids have both the shear modulus as well as the bulk modulus of elastically. (d) A pulse of sound consists of a combination of waves of different wavelength. In a dispersive medium these waves travel with different velocities giving rise to the distortion in the wave.
