MCQEasy1 mark
1
Choose the correct answers to the questions from the given options. (Do not copy the questions, write the correct answers only.)
A coil wound around a piece of soft iron can become an electromagnet only when: (a) the circuit is open. (b) a magnetic compass is present in the vicinity. (c) a galvanometer is connected to the circuit. (d) a current flows in the circuit.
Topic: Magnetic effect of current / electromagnetic induction
Previous-year question practice database
Try it
Pick an option and check your answer. The full worked answer is below either way.
Answer
Exam answer
(d) a current flows in the circuit.
Explanation
Current through the coil magnetises the soft iron core.
More from Electromagnetism
The diagram below shows the top view of the Wire A shown by a cross (X), carrying current into the plane of the paper. Which of the compasses is correctly aligned with the magnetic field produced by the current carrying wire?
(a) Only 1 is aligned
(b) Only 2 is aligned
(c) Both 1 and 2 are aligned
(d) Both 1 and 2 are not aligned2026intensifies the magnetic field.2026maintains electrical contact between the rotating parts and the external circuit.2026in the direction of the motion of the magnet?2026in the opposite direction of the motion of the magnet?2026The following figure shows a small bar magnet falling freely through a copper ring. For the observer at A, the direction of the induced current will be :
(a) clockwise when magnet is above and below the ring
(b) anticlockwise when magnet is above and below the ring
(c) anticlockwise when magnet is above the ring and clockwise when the magnet is below the ring
(d) clockwise when magnet is above the ring and anticlockwise when the magnet is below the ring2025