According to Hooke's law of elasticity, if stress is increased, then the ratio of stress to strain

Hooke in 1679 , showed experimentally that if strain is small, then the stress is proportional to strain. The ratio of stress to strain is constant for material of the given body and is called modulus of elasticity $E$. Thus, $E=\frac{\text { stress }}{\text { strain }}=$ constant Hence, if stress is increased, then the ratio of stress to strain remains constant.