Magnetic field lines can netiher emanate from a point nor end on a point. Yet the field lines outside a bar magnet do seem to start from the North pole and end on the South pole. Does the second fact contradict the first? Explain.

The direction of the neutral points is on the equitorial line of a bar magnet, when the north pole of the magnet is pointing towards

What is magnetic dipole? Derive an expression for magnetic field intensity at a point on the equitorial line of a bar magnet.

Can a magnetic field line from a closed loop? Explain.

Magnetic field lines show the direction (at every point) along which a small magnetised needle aligns (at the point). Do the magnetic field lines also represent the lines of force on a moving charged particle at every point ?

use (i) the Ampere's law for H and (ii) continuity of lines of B, to conclued that inside a bar magnet, (a) lines of H run from the N pole to S pole, while (b) lines of B must run from the S pole to N pole.

What is a magnetic dipole? Obtain for the strength of magnetic field at a point at distance r from its centre on axial line. Find the strength of the field in special case, when the length of the magnet is very small as compared to the distance r.

Answer the following questions: A magnetic field that varies in magnitude from point to point but has a constant direction (east to west) is set up in a chamber. A charged particle enters the chamber and travels undeflected along a straight path with constant speed. What can you say about the initial velocity of the particle?