Concept:A commutator acts as a mechanical switch in a DC motor to keep the torque in one direction.
Explanation:In a DC motor, the coil rotates inside a magnetic field.
After every half rotation, the direction of the force on each side of the coil would normally reverse.
The commutator, along with the brushes, reverses the direction of the current flowing through the coil at that instant.
This reversal happens exactly after every half rotation.
As a result, the torque continues to act in the same direction and the coil keeps rotating continuously.
Therefore, the correct purpose is to reverse the current direction after every half rotation.
Answer:A. reverse the direction of the current after every half rotation