Physics - Heat & Thermo Question with Solution | TestHub

Rubber is made of long, coiled polymer chains. On heating, the thermal vibrations of the chain segments increase, mostly sideways to the chain. The sideways motion pulls the chain ends closer, so the chains coil up more and the sample shortens (entropic elasticity). In ordinary solids the stretching of bonds dominates and the sample expands, but in a stretched rubber the coiling effect dominates. Both are true. The Reason gives the physical cause of the Assertion. Correct option: (A).