Question

what is the use of a metallic strip​

Answer 1

heya mate...

Bimetallic strips were commonly used in thermostats. The two metals would expand at different rates and therefore bend.

The heat of the fire, causes the brass and iron strips to expand, ultimately resulting in the bending of the bimetallic strip, which on bending touches the screw adjacent to it, thus completing the circuit. Once the circuit is complete, the bell begins to ring.

hope it helps you