Question 412Electricity & Electronics - Assistant Engineer

The correct answer is D) The motor will slow down by the process of dynamic braking. When a DC motor's armature and field are connected across a resistor while the motor is disconnected from its power supply, this sets up a dynamic braking circuit. In this configuration, the motor's momentum causes it to generate a back EMF voltage, which creates a current flowing through the resistor. This current opposes the motor's rotation, resulting in the motor slowing down through the process of dynamic braking. The other answer choices are incorrect because they do not accurately describe the function of this circuit configuration. Across the line starting, automatic strip heaters, and reversing controller circuits involve different electrical connections and purposes for DC motors.