Question

NTSE physics question Two electromagnets are made by wrapping a few turns of wire on similar nails and passing the same amount of current through them. The number of turns of the wire wrapped over the two iron nails are in the ratio 2:1. The strength of which electromagnet is stronger Please explain! Thanks

Answer 1

     A magnetic field is created by the current flowing in each turn/loop.  The magnetic field inside the loop is the resultant of the magnetic fields due to all the turns.  If the turns are very few, then the magnetic field due to each turn is added.  So more the number of turns, more the strength of magnetic field.        So answer will be  2: 1.

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   The magnetic field depends on the number of turns of coil per unit length and the current.