question_answer

In case of steel wire or a metal wire, the elastic limit is reached when

A)  the wire just break

B)  the load is more than the weight of wire

C)  elongation is inversely proportional to the tension

D)  None of the above

Correct Answer: D

Solution :

 According to Hookes law, the stress produced in a body is proportional to the strain. But this proportionality exists for small strains only. When a load is applied to a damped wire, the length of wire goes on increasing part OA of the graph is straight line, indicating that upto point A, increase in length is directly proportional to load. After point A on further increasing the load, the increase in length is no longer proportional to load, however till point B the elastic property exists in the wire. The stress at point B is called elastic limit. Beyond B is the wire does not return to its original position, but its length is permanently increased, Hence, none of the given statements is true.