Question

Modulus of rigidity of ideal liquids is ______.

विकल्प

• infinity.

• zero.

• unity.

• some finite small non-zero constant value.

Answer 1

Modulus of rigidity of ideal liquids is zero.

Explanation:

Modulus of Rigidity: Within limits of proportionality, the ratio of tangential stress to the shearing strain is called the modulus of rigidity of the material of the body and is denoted by η

i.e. η = `"Shearing stress"/"Shearing strain"`

In this case, the shape of a body changes but its volume remains unchanged.

Consider a cube of material fixed at its lower face and acted upon by a tangential force F at its upper surface having area A.

Only solids can exhibit a shearing as these have a definite shape.

In liquids, η = 0

So, the frictional (viscous) force cannot exist in the case of an ideal fluid and since they cannot sustain shearing stress or tangential forces are zero, there is no stress developed.