Question

The graph shows the behaviour of a length of wire in the region for which the substance obeys Hooke’s law. P and Q represent

• A. P = applied force, Q = extension
• B. P = extension, Q = applied force
• C. P = extension, Q = stored elastic energy
• D. P = stored elastic energy, Q = extension

Answer 1

Answer: (C)

P = extension, Q = stored elastic energy

Answer 2

The graph between applied force and extension will be straight line because in elastic range applied force $\propto$ extension, but the graph between extension and stored elastic energy will be parabolic in nature.

As $U = \frac{1}{2}kx^{2}$ or $U \propto x^{2}$