Magnetism and Matter · Question 7

JEE Main 2025 (Online) 3rd April Evening ShiftMCQEasy📈 Topic in 6% papers+4−1

A magnetic dipole experiences a torque of 80 3 N m when placed in uniform magnetic field in such a way that dipole moment makes angle of 60 with magnetic field. The potential energy of the dipole is:

-40 3 J
-80 J
80 J
-60 J

Answer

(2) -80 J

Solution

= mB

⇒ 80 3 = mB 32 ⇒ mB = 160 J

U = -mB = -160 12

∴ U = -80 J

Answer: (2)

JEE Main 2025 (Online) 3rd April Evening Shift

Keep practising — Magnetism and Matter

The relationship between the magnetic susceptibility ( ) and the magnetic permeability ( ) is given by : ( 0 is the permeability of free space and r is relative permeability)

= 0 - 1
= r 0 + 1
= r + 1
= 1 - 0

JEE Main 2025 (Online) 2nd April Morning Shift

[figure] A bar magnet has total length 2l = 20 units and the field point P is at a distance d = 10 units from the centre of the magnet. If the relative uncertainty of length measurement is 1\%, then uncertainty of the magnetic field at point P is :

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All JEE Main Physics chapters

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