NEETPhysicsMechanical Properties of Solids
Assertion (A): The stretching of a coil is determined by its shear modulus. Reason (R): Shear modulus changes only the shape of a body, keeping its dimensions unchanged.
Options
- ABoth A and R are true and R is the correct explanation of A.
- BBoth A and R are true but R is not the correct explanation of (A ).
- CA is true but R is false.
- D(A ) is false but (R ) is true.
Correct answer
D. (A ) is false but (R ) is true.
Step-by-step solution
The stretching of a coil primarily involves a change in its length, which is governed by its Young's modulus (related to tensile or compressive stress), not its shear modulus. Shear modulus is associated with changes in the shape of a body due to shearing forces, where the dimensions remain largely unchanged. Therefore, Assertion (A) is false because stretching a coil is related to Young's modulus. Reason (R) is true as it correctly describes the effect of shear modulus on a body's shape without altering its dimens