CIE iGCSE Co-Ordinated Science P4.5.5 The d.c. motor Exam Style Questions Paper 2
Question
What is the purpose of the commutator in a direct current (d.c.) motor?
(A) It reverses the direction of the current in the coil every half turn.
(B) It reverses the direction of rotation of the coil every complete turn.
(C) It reverses the direction of rotation of the coil every half turn.
(D) It reverses the magnetic field due to the permanent magnet every complete turn.
▶️Answer/Explanation
Ans: A
Question
The diagram shows a motor. One part of the motor is labelled X.
What is the name of part X and how does it help the motor to work?
▶️Answer/Explanation
Ans : B
Question
The diagram shows an electrical device.
What is this electrical device?
A. a d.c. motor
B. an a.c. generator
C. a transformer
D. a solenoid
▶️Answer/Explanation
Answer: A
Explanation: The presence of a split-ring commutator and carbon brushes indicates that this is a d.c. motor. The commutator reverses the current direction in the coil every half-turn, ensuring continuous rotation in one direction when connected to a direct current (d.c.) supply.