Objective:

To observe the magnetic field lines around current carrying solenoid.

Theory:

1. A coil of many circular turns of insulated copper wire wrapped closely in the shape of a cylinder is called a solenoid.
2. The pattern of the magnetic field lines around a current-carrying solenoid is illustrated in Fig.1.
3. The pattern of the field is similar to magnetic field around a bar magnet. One end of the solenoid behaves as a magnetic north pole, while the other behaves as the south pole.
4. The field lines inside the solenoid are in the form of parallel straight lines. This indicates that the magnetic field is the same at all points inside the solenoid. That is, the field is uniform inside the solenoid.

Fig 1: Field lines of the magnetic field through and around a current
carrying solenoid.

Source: NCERT class X lab manual