Question

The property of a medium necessary for wave propagation is its
A. elasticity
B. low resistance
C. inertia
D. all of the above

Answer 1

Hint: The wave that requires a medium in order to propagate is called an elastic wave. Example of an elastic wave is sound. There is another type of wave called electromagnetic wave which does not require a medium. In this problem, the wave referred to, here is the elastic wave.

Complete step-by-step answer:
The wave is a propagating dynamic disturbance of one or more quantities, which is described by a wave equation. In the physical waves, there are at least two field quantities in the wave medium involved. Waves can be periodic; in which case those quantities oscillate repeatedly about a resting value at a particular frequency.
In the mechanical or elastic wave, stress and strain fields oscillate about an equilibrium. A mechanical wave is a local deformation in some physical medium that propagates from particle to particle by creating local stresses that cause strain in neighbouring particles too.
Now, after the stress has been removed, the particles have to retain their original state. The property of a material to return it to its original state after deformation is applied, is called elasticity. Thus, the elasticity is a required property for wave propagation.
When the deforming force is applied on the molecules, the deformation must be finite enough to cause vibration of the particles, thus making the wave propagate. However, this does not happen if the resistance to the deforming force is too high to resist the vibration thereby, causing the wave to discontinue propagating. Hence, the material should have a low resistance.
Also, when the deforming force is applied, the particles should not undergo large displacements thereby breaking the continuity in the wave propagation. When the particles undergo deformation, it should resist the deformation to a slight extent due to the inherent property called inertia. Thus, inertia is a necessary requirement for the medium.
To summarise, for the propagation of waves, the conditions required for the propagating medium are elasticity, low resistance, and inertia.

Hence, the correct option is Option D.

Note: There are 2 manners in which the waves propagate. They are: Longitudinal and Transverse.
- In longitudinal waves, the particles vibrate in the same direction as that of the direction of propagation of waves.
- In a transverse wave, the particles vibrate at right angles to that of the direction of propagation of the wave.