Question

Behaviour of wire under continuously increasing stress

Answer 1

On gradually increasing the load attached to the wire, the behaviour of the wire changes. At any point in time, we can measure, stress and the corresponding strain.

Initially stress is directly proportional to strain and Hooks law is obeyed in this region. The region OA is said to be elastic. The point A is called elastic limit.

On further increasing the load attached to the wire, a small increase in stress causes a large increase in strain. This region AA1is said to be partly elastic and partly plastic.

At the point B called Yield point, the strain begins to increase without the change in stress. The tangent to the point B is parallel to strain.

Next region is called the break down region, where on loading the wire, the wire becomes thin and breaks. The point C at which the wire breaks is called breaking point.