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In a DC motor, what role does the split-ring commutator play?
AIncreases the current strength continuously
BReverses current direction every half rotation
CStores the back EMF in a capacitor
DActs as a fuse during overload conditions
Answer & Solution
Correct answer: B. Reverses current direction every half rotation
1. The split-ring commutator is a metal ring cut into two halves.
2. As the armature rotates, the brushes contact each half in turn.
3. This reverses the direction of current through the armature every half rotation.
4. Reversing the current keeps the torque acting in the same rotational direction.
5. Without the commutator, the motor would stop oscillating.
6. So the commutator reverses current direction every half rotation.
_Source: NCERT Class 10 Science Ch 13 'Magnetic Effects of Electric Current' (learncbse.in extract)_
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