question_answer

A bimetallic strip is made of two strips A and B having coefficient of linear expansion as\[{{\alpha }_{A}}\]and da. If\[{{\alpha }_{A}}>{{\alpha }_{B}},\] which one of the following describes the behaviour of the metallic strip when heated?

A)  Strip will bend only when \[\frac{{{\alpha }_{A}}+{{\alpha }_{B}}}{2}>({{\alpha }_{A}}-{{\alpha }_{B}})\]

B)  Strip will bend but will not elongate

C)  Strip will bend with metal A as the outer side

D)  Strip will bend with metal B as The outer side

Correct Answer: C

Solution :

 As\[{{\alpha }_{A}}\]is more than\[{{\alpha }_{B}}\]so the length of metal A after rise in temperature will be more than that of metal B. The bimetallic strip will bend in such a manner that metal A will fall on the outer side and B will lie on the inner side of the bent strip.