Question

The pattern of the magnetic field produced inside a current carrying solenoid is :

A uniform magnetic field exists in the plane of paper as shown in the diagram. In this field, an electron (e⁻) and a positron (p⁺) enter as shown. The electron and positron experience forces :

The current carrying device which produces a magnetic field similar to that of a bar magnet is :

What happens when a bundle of wires of soft iron is placed inside the coil of a solenoid carrying a steady current ? Name the device obtained. Why is it called so ?