Final answer:
A switch that automatically interrupts an electric circuit at the first sign of an overload is called a b. circuit breaker. It is a restorable switch that acts quickly during an overload, protecting the circuit from damage.
Step-by-step explanation:
Automatic Overload Protection Device
The device that automatically interrupts or shuts off an electric circuit at the first indication of an overload is called a circuit breaker. This device functions as an automatic but restorable electric switch. Unlike fuses, which permanently break the circuit when overheated by excessive current, a circuit breaker can be reset after tripping. Circuit breakers contain a bimetallic strip that bends when overheated due to excessive current, triggering a spring mechanism that breaks the electrical connection. They are designed to react quickly to protect equipment and ensure safety.
Circuit breakers are preferred over fuses for household and industrial applications because they can be reset instead of replaced. They use various technologies, including insulating gases and gas jets, to extinguish electrical arcs that may occur during the interruption of high-voltage current flows. It's also important to note the presence of ground fault circuit interrupters (GFCIs), which are another safety device commonly used in environments where water is present, like bathrooms and kitchens.
In summary, the correct answer to the question is option b) Circuit breaker.