Under what condition is the contactor K1 activated according to the program?

The contactor K1 is activated under the specific condition that pushbutton PB2 is pressed and sensor B1 is activated. This indicates that K1's activation is contingent upon both inputs working together, forming a logical AND combination. This is typical in control circuits where certain safety or operational requirements need to be met before a device, such as a contactor, is energized.

By requiring both the pushbutton and the sensor to be activated, this condition ensures that the intended action is deliberate, reducing the risk of unintended operations that could occur if either input were enough on its own. Such configurations are common in industrial environments where both manual and automatic inputs are needed for safety and operational reliability.