Question

Assertion Young's modulus for a perfectly plastic body is zero.
Reason For a perfectly plastic body, restoring force is zero.

• A. If both Assertion and Reason are true and the Reason is correct explanation of the Assertion
• B. If both Assertion and Reason are true but Reason is not correct explanation of the Assertion
• C. If Assertion is true but Reason is false
• D. If Assertion is false but the Reason is true

Answer 1

Answer: (A)

Young's modulus of a material, $Y=\frac{\text { strain }}{\text { strain }}$
and Stress $=\frac{\text { Restaring force }}{\text { Area }}$
As, restoring force is zero $\therefore Y=0$