Final answer:
To indicate when a motor stops working, a parallel circuit with a lamp can be used alongside the motor circuit, set to light up when the motor circuit is broken, thus the lamp remains off while the motor runs and turns on when it stops.
Step-by-step explanation:
To build a circuit where the lamp indicates when the motor stops working, you would need to set up a parallel circuit alongside the motor that includes the lamp and a power source. The circuit would function in such a way that when the motor is working (the switch in its path is closed), it completes the circuit and the lamp stays off due to the motor drawing all the current. However, when the motor stops working (the switch in its path is open), the circuit containing the lamp completes and the lamp turns on, indicating that the motor has stopped.
An example circuit setup would be as follows:
- A power source (such as a battery) with positive and negative terminals.
- A switch that can open or close the circuit to the motor.
- The motor connected in series with the switch.
- The lamp connected in parallel with the motor, possibly with its own switch to avoid short-circuiting when the main motor is working.
The lamp acts as an indicator that is triggered by the motor circuit being open. Therefore, when the switch to the motor is open, indicating that the motor has stopped, the lamp will light up.