Concepts Of Physics MCQ Edition [Volume 2]PhysicsPermanent Magnets
As illustrated in the figure, two short magnets with equal dipole moments M are joined perpendicularly at their centres. What is the magnitude of the magnetic field at a distance d from the centre along the bisector of the right angle?
Options
- A₀ 4 2 2 M d^3
- B₀ 4 2M d^3
- C₀ 4 2 M d^3
- D₀ 4 M d^3
Correct answer
A. ₀ 4 2 2 M d^3
Step-by-step solution
Let the centre of the two magnets be at the origin (0,0) . The horizontal magnet has its South pole on the left and North pole on the right. Its magnetic dipole moment is directed from South to North, so M ₁ = M i . The vertical magnet has its South pole at the bottom and North pole at the top. Its magnetic dipole moment is also directed from South to North, so M ₂ = M j . The net magnetic dipole moment of the system is the vector sum of the individual dipole moments: M _ net = M ₁ + M ₂ = M i + M j The magnitude o