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
Answer: (D) **(A)** is true but **(R)** is false
(A): when a coil spring is stretched, the length of its wire hardly changes; the wire is twisted. The extension is governed by the shear (rigidity) modulus. True.
(R): steel has much higher elastic moduli and tensile strength than copper, so a steel spring is the stronger one. False.
Solution by Sreeraj P, M.Sc Physics