99 Percentile Qs Bank for JEE MainPhysicsMagnetic Properties of Matter
The mid points of two small magnetic dipoles of length d in end-on positions, are separated by a distance x x > > d . The magnitude of force between them is proportional to x − n where n is :
Options
- A3
- B4
- C2
- D1
Correct answer
B. 4
Step-by-step solution
B = μ o 4 π 2 M x 3 for end-on position U = − M → . B → = μ o 4 π 2 M 2 x 3 F = − d U d x = − 3 μ o 4 π 2 M 2 x 4 therefore force between them ∝ x - 4