What happens when a bimetallic strip reaches a certain temperature?

When a bimetallic strip reaches a certain temperature, it bends and triggers the alarm.

Bimetallic strips are composed of two different metals that expand at different rates when heated. As the temperature rises, the differential expansion causes the strip to bend. This bending action is often integrated into fire detection systems, where the movement can activate a switch or signal within the alarm system. This mechanical response is crucial for initiating an alarm, thereby alerting occupants and coordinating emergency responses.

The other options reference actions that do not directly involve the physical properties of a bimetallic strip or are not typical responses associated with this component. Therefore, the response of bending and activating the alarm highlights the function of bimetallic strips in fire safety systems effectively.