Draw a diagram to represent the magnetic field lines along the axis of a current carrying solenoid. Mark arrows to show the direction of current in the solenoid and the direction of magnetic field lines.

The diagram in figure shows a spiral coil wound on a hollow cardboard tube AB. A magnetic compass is placed close to it. Current is switched on by closing the key.

(a) What will be the polarity at the ends A and B?

(b) How will the compass needle be affected? Give reason.

Draw a labelled diagram showing the three magnetic field lines of a loop carrying current. Mark the direction of current and the direction of magnetic field by arrows in your diagram.

By using a compass needle describe how can you demonstrate that there is a magnetic field around a current carrying conductor.