Question

The moduli of elasticity for a substance are Young’s modulus, Bulk modulus and Modulus of rigidity. All the three moduli of elasticity are possessed by

• A. gases and liquids
• B. solids and liquids
• C. solids only
• D. solids and gases

Hint:

Modulus of rigidity exists only when a material can resist shear deformation, which is possible only in solids.

Answer 1

The Correct Option is C

Step 1: Understand different elastic moduli.
Young’s modulus, Bulk modulus and Modulus of rigidity describe resistance to stretching, volume change and shape change respectively.
Step 2: Behaviour of solids.
Solids can resist change in length, volume and shape, hence they possess all three elastic moduli.
Step 3: Behaviour of liquids and gases.
Liquids and gases cannot resist shear stress, so modulus of rigidity is zero for them. Hence, they do not possess all three moduli.
Step 4: Final conclusion.
Only solids possess Young’s modulus, Bulk modulus and Modulus of rigidity.