What principle does a DC motor operate on?

A DC motor operates on the principle of converting electrical energy into mechanical energy. This process takes place through the interaction between the magnetic field produced by the current flowing through the motor's windings and the magnetic field of the motor's permanent magnets or electromagnets. As direct current flows through the windings, it creates a magnetic force that generates torque, causing the motor's rotor to turn. This conversion is fundamental to the functioning of DC motors, enabling them to perform mechanical tasks by transforming supplied electrical energy into motion.

The other options do not accurately reflect how a DC motor operates. The conversion of mechanical energy to electrical energy pertains to generators, not motors. The conversion of direct current to alternating current is related to inverters or converters, not the operation of motors. Lastly, while the interaction between electrical current and resistors is a fundamental principle in electrical circuits, it does not specifically describe the function of a DC motor, which centers around the conversion of electrical energy to mechanical energy through magnetic interaction.