A rubber of volume 2000 cc is alternately subjected to tension and released. The figure shows the stress-strain curve of rubber. Each curve is a quadrant of an ellipse. The amount of energy lost as heat per cycle per unit volume will be

Hystersis loss corresponding to elasticity per unit volume of a substance is given by the area of hysteresis loop, i.e., stress-strain curve corresponding to one complete loading and deloading. Area of an ellipse =π× semi-major axis × semi-minor axis A1=14π×8×4×102 and A2=14π×8×4×102 Also, A3=8×4×102 Area of hysteresis loop is A=A1+A2−A3A=2π4×8×4×102−8×4×102=π2−1×32×102J   = work done per cycle     = energy lost per cycle per unit volume