Solution:Concept: A permanent magnet produces a magnetic field on its own, whereas an electromagnet produces one temporarily as a result of the current passing through the wire around an iron core.
The major advantage of electromagnets is that they can control their attractive drag by turning the magnet on or off and changing the current. They too have a more grounded draw than changeless magnets. Agreeing to a few estimations, the greatest electromagnet is 20 times more effective than the foremost effective changeless magnet.
Hence, the correct answer is option 4.