A straight wire lying in a horizontal plane carries a current from north to south. (a) What will be the direction of magnetic field at a point just underneath it? (b) Name the law used to arrive at the answer in part (a).

A wire, bent into a circle, carries current in an anticlockwise direction. What polarity does this face of the coil exhibit?

How is the magnetic field due to a solenoid carrying current affected if a soft iron bar is introduced inside the solenoid?

Name one device that uses an electromagnet.