56. In figure «1» of the illustration, what type of circuit breaker trip element is featured

Figure 1 illustrates a thermal trip circuit breaker, which operates by heating caused by load current. This design incorporates a heater/bimetal element in series with the load, causing the element to bend and trip the breaker when overloaded. Other options are incorrect: ambient compensated trips include additional components for temperature compensation, magnetic trips respond to high fault currents via an electromagnetic coil, and shunt trips are energized remotely via a separate control circuit.