7
QuizMultiple Choice

Electricity and Magnetism — Test

Question 7 • Physical Science

Which would ultimately cause the armature in an electric motor to spin?

Answer
A
The gap in the commutator closes.
B
The current in the armature is reversed.
C
The current in the armature stops.
D
The commutator loses contact with the brushes.

Explanation

As the armature turns through each half-rotation, the commutator reverses the current in its coil. This reverses the magnetic force on the armature at the right time, keeping the turning force in the same rotational direction so the armature continues to spin. The correct choice is “The current in the armature is reversed.”

AI-written and checked against the verified answer.

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