Magnetic field lines can be entirely confined within the core of a toroid, but not within a straight solenoid.Why?

The magnetic field inside a solenoid is

The magnetic field inside a long solenoid is

In radial magnetic field lines of force are

What is the nature of the magnetic field inside the solenoid?

The magnetic field intensity due to a long solenoid at its end is

Magnetic field lines are always nearly normal to the surface of a ferromagnet at every point. (This fact is analogous to the static electric field lines being normal to the surface of a conductor at every point.) Why?

The magnetic field produced around a straight line wire when current flows through it is

Find the percent increase in magnetic field B when the space within a current-carrying toroid is filled with aluminium. The susceptibility of aluminium is 2.1xx10^-5 .

Draw the magnetic force lines of a current carrying finite solenoid?

Choose the correct statement/s: (i) Magnetic field lines try to expand in length. (ii) Magnetic field lines repel each other laterally. (iii) Magnetic field lines attract each other laterally. (iv) Magnetic field lines are crowded in region where magnetic induction has least value.