Question

Two identical short bar magnets are placed at 120° as shown in the figure. The magnetic moment of each magnet is M. Then the magnetic field at the point P on the angle bisector is given by




(1) µ04π·Md3 (2) µ04π·2Md3 (3) µ04π·2√2Md3 (4) Zero

Answer 1

Suppose P is at the axial line of the bar magnet at a distance r ,

Therefore,

B on the axial line,

B = u.•/4π(2M/r³)

Answer 2

Welcome dear,

● Answer -
B = (μ0/4π) M/d^3

● Explaination -
# Given -
θ = 120°

# Solution -
Dipole moment at angle bisector is -
M' = √[M^2 + M^2 + 2M.M.cosθ]
M' = M √[2(1-0.5)]
M' = M

Magnetic field at angle bisector is calculated by -
B = (μ0/4π) M'/d^3
B = (μ0/4π) M/d^3

Hope this helps you ...