Which of the following is not the correct method to make permanent magnets?
A. Using a bar magnet to stroke a steel bar
B. Using two bar magnets to stroke a steel bar
C. Placing a steel bar in a solenoid that connects to a DC supply
D. Placing a steel bar in a solenoid that connects to an AC supply, then slowly withdrawing the steel bar away from the solenoid in West-East direction
Answer:D
Which of the following is not the correct method to make permanent magnets?
A. Using a bar magnet to stroke a steel bar B. Using two bar magnets to stroke a steel bar C. Placing a steel bar in a solenoid that connects to a DC supply D. Placing a steel bar in a solenoid that connects to an AC supply, then slowly withdrawing the steel bar away from the solenoid in West-East direction