Which type of switch can be operated by thermostats using coiled bimetal strips?

The correct choice involves understanding the operation of a switch that can be actuated by thermostats incorporating coiled bimetal strips. Bimetallic strips are made from two different metals that expand at different rates as they heat up. When a thermostat uses these strips, an increase in temperature causes the strip to bend, actuating the switch.

Mercury switches utilize this principle effectively. In a mercury switch, the tilting action of the bimetallic strip causes mercury to flow within the switch, completing or breaking the circuit. This design is particularly well-suited for applications like thermostats where reliable and accurate temperature control is necessary.

In comparison, despite other types of switches also being useful in different contexts, they do not operate using bimetal strips in the same way. For instance, electronic switches rely on semiconductor technology and are not directly influenced by temperature changes through mechanical movement. Relay switches, while they can be used for a variety of control applications, typically involve electromagnetic coils rather than bimetallic action. Mechanical switches may be manually operated or controlled but do not inherently utilize the principle of bimetal expansion to function.

Therefore, mercury switches represent the specific type of switch that effectively utilizes coiled bimetal strips, making them