(a) State Gauss's law for magnetism. Explain its significance.
(b) Write the four important properties of the magnetic field lines due to a bar magnet.
(b) Write the four important properties of the magnetic field lines due to a bar magnet.
Solution
(a) Gauss's law for magnetism states that the net magnetic flux through any closed (Gaussian) surface is zero:
Significance: magnetic field lines are always continuous closed loops, so the number of lines entering a closed surface equals the number leaving it. This means isolated magnetic monopoles do not exist - the simplest magnetic entity is a dipole.
(b) Four properties of the field lines of a bar magnet:
(i) They are closed, continuous loops (outside they run N to S, inside S to N).
(ii) Two field lines never intersect.
(iii) The lines are crowded where the field is strong and spread out where it is weak.
(iv) The tangent to a field line at any point gives the direction of there.
Significance: magnetic field lines are always continuous closed loops, so the number of lines entering a closed surface equals the number leaving it. This means isolated magnetic monopoles do not exist - the simplest magnetic entity is a dipole.
(b) Four properties of the field lines of a bar magnet:
(i) They are closed, continuous loops (outside they run N to S, inside S to N).
(ii) Two field lines never intersect.
(iii) The lines are crowded where the field is strong and spread out where it is weak.
(iv) The tangent to a field line at any point gives the direction of there.
CBSE Class 12 Board · 2019 · Subjective