A bar magnet of length 14 cm is placed in the magnetic meridian with its north pole pointing towards the geographic north pole. A neutral point is obtained at a distance of 18 cm from the center of the magnet. If B H = 0 . 4 G , the magnetic moment of the magnet is 1 G = 10 - 4 T

Step-by-step solution

i.e. 2 μ 0 4 π m r 2 × 7 r = 0 . 4 × 10 - 4 ⇒ 2 × 10 - 7 × m × 7 7 2 + 18 2 3 / 2 × 10 4 = 0 . 4 × 10 - 4 m = 4 × 10 - 2 × 373 3 / 2 14 ⇒ M = m × 14   cm = m × 14 100 = 0 . 04 × 373 3 / 2 14 × 14 100 ⇒ M = 4 × 10 - 4 × 7203 . 82 = 2 . 88   J   T - 1 .