Given below are two statements: One is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The stretching of a spring is determined by the shear modulus of the material of the spring. Reason (R): A coil spring of copper has more tensile strength than a steel spring of same dimensions. In the light of the above statements, choose the most appropriate answer from the options given below:
Physics · Properties of solid and fluid · properties of solid stress ,strain and modulus of elasticity
NEET 2022 NEET Previous Year

Question

Given below are two statements: One is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The stretching of a spring is determined by the shear modulus of the material of the spring. Reason (R): A coil spring of copper has more tensile strength than a steel spring of same dimensions. In the light of the above statements, choose the most appropriate answer from the options given below:

Physics · Properties of solid and fluid · properties of solid stress ,strain and modulus of elasticity

NEET 2022 NEET Previous Year

G1 Physics · Accepted Answer

Step 1: For a helical spring subjected to an axial force, the spring wire mainly undergoes torsion (shear deformation). Step 2: For the same coil geometry, spring stiffness k is proportional to shear modulus G; for a close-coiled helical spring, k = Gd⁴/(8nD³), where d is the wire diameter, D is the mean coil diameter, and n is the number of active turns. Step 3: Therefore, Assertion (A) is true: spring extension depends on G. Step 4: The Reason (R) is false. Copper does not generally have a hi…