Respuesta :

When the property of the medium changes.

Answer:

It depends on the elasticity of the medium

Explanation:

If the travelling wave is a longitudinal wave then the speed of the wave is given by the formula

[tex]v = \sqrt{\frac{E}{\rho}}[/tex]

now we know that if the elastic property of medium or the density of medium will change then the wave will change its velocity

for solids we can say that

[tex]E = Y[/tex](Young's Modulus)

and for liquids and gases it is given as

[tex]E = B[/tex](Bulk Modulus)

so we can say that velocity of the wave will change due to change in medium because it depends on elasticity of the medium and its density