Question

A bimetallic strip consists of metals $A$ and $B$. It is mounted rigidly as shown. The metal $A$ has higher coefficient of expansion compared to that of metal $B$. When the bimetallic strip is placed in a cold bath, it will:

• A. Not bend but shrink
• B. Neither bend nor shrink
• C. Bend towards the right
• D. Bend towards the left

Answer 1

The correct option is D Bend towards the left

Given, ${\alpha }_A>{\alpha }_B$

Length of both strips will decrease because their temperature will decrease when placed in cold bath.

We know, $\Delta L=L\alpha \Delta T$
So, change in length: $\Delta L_A>\Delta L_B$

$\Rightarrow A$ will be shorter and hence will bend towards left.