Question

Draw a labelled diagram to show the pattern of magnetic field lines produced due to a current carrying straight conductor. Mark on it the direction of current in the conductor and the direction of magnetic field lines.

Name the device used to magnetise a piece of magnetic material. Draw a labelled diagram to show the arrangement used for the magnetisation of a cylinder made of soft iron.

Ravi performed an experiment in his school laboratory to study the magnetic effect of electric current. He passed electric current through a straight copper conductor placed near a magnetic compass. He observed that the compass needle deflected when current flowed through the conductor. When the direction of current was reversed, the direction of deflection of the compass needle also reversed. Later, Ravi used a solenoid connected to a battery and placed a soft iron core inside it. He observed that the solenoid behaved like a bar magnet when current flowed through it and lost its magnetism when the current was switched off.

Which of the following appliances uses the magnetic effect of electric current?