Question

In the figure given below, a coil is placed between two permanent magnets and it is rotated with the help of an axle, on which two rings R1 and R2 are internally attached. B1 and B2 represents metallic brushes. G represents galvanometer.

The current flowing through the circuit reverses direction periodically, such a current is called alternating current. The current can be made direct by ___.

• A. changing the commutator to split ring type
• B. replacing the north pole of the permanent magnet by a south pole
• C. changing the position of the Galvanometer to the stationary part of the circuit
• D. replacing the metallic brushes by fibre brushes

Answer 1

The correct option is A

changing the commutator to split ring type

A commutator reverses the direction of current. If the current has a natural tendency to reverse direction as in this case, a commutator like a split ring maintains the current in the same direction.

A split ring as the name suggests has a split in between which lets one part of the ring always connect to the part moving up and other to the one moving down and thus, the current direction remains the same. The same concept is used in an electric motor.