Ncert Exercises & Solutions

For an ideal liquid,

(a)	the bulk modulus is infinite.
(b)	the bulk modulus is zero.
(c)	the shear modulus is infinite.
(d)	the shear modulus is zero.

Choose the correct option:

(1) Hint: An ideal fluid provides zero resistance to the shear forces.

Step 1: Find the Bulk modulus of the liquid.

As an ideal liquid is not compressible, hence, change in volume,

∆ V = 0

Bulk modulus B =

\frac{Stress}{Volume strain} = \frac{F / A}{∆ V / V} = \frac{F}{A} \times \frac{V}{∆ V} = \infty

Compressibility, K =

\frac{1}{B} = \frac{1}{\infty} = 0

Step 2: Find the shear modulus of the liquid.

As there is no tangential (viscous) force exists in the case of an ideal fluid, hence, shear modulus = 0