Question

Which of the following is not true for an electromagnet and permanent magnet

• A. An electromagnet can be made strong, in comparision to a permanent magnet
  
• B. An electromagnet can be demagnetized by stopping the flow of current but not true permanent magnet
• C. An electromagnet can change the polarity but not a true permanent magnet.
• D. Current is required for magnetic field in both electromagnet and permanent magnet

Answer 1

The correct option is D

Current is required for magnetic field in both electromagnet and permanent magnet

Current is required for magnetic field only in an electromagnet and not a permanent magnet. The magnetic field is already present in permanent magnet, hence (d) is wrong