ANS:B - The elastic behaviour of rubber under compression is the same as its behaviour under tension.

The elastic behavior of rubber under compression is the same as its behavior under tension is incorrect. Rubber exhibits different mechanical behaviors under compression and tension due to its unique molecular structure and the way its polymer chains respond to applied loads.

1. Under Compression: When a compressive force is applied to rubber, the polymer chains are pushed closer together. In this situation, the polymer chains tend to resist compression by pushing back against the applied force. However, rubber is a highly nonlinear material, and its response to compression is often characterized by various phenomena such as strain crystallization, stress softening, and hysteresis. These behaviors result in a complex stress-strain relationship that is different from the linear behavior observed in elastic materials under tension.
2. Under Tension: When a tensile force is applied to rubber, the polymer chains tend to straighten out and align along the direction of the applied force. This alignment allows rubber to stretch and elongate. Similar to compression, the behavior of rubber under tension is also nonlinear. Rubber typically exhibits stress-strain curves that are characterized by initial stiffness followed by increasing deformation with relatively little increase in stress, leading to necking and ultimate failure.

In summary, the elastic behavior of rubber under compression is not the same as its behavior under tension. Rubber displays nonlinear and complex mechanical behaviors under both compression and tension, with distinct stress-strain responses in each loading condition.