Q. A magnet of length 14 cm and magnetic moment M is broken into two parts of length 6 cm and 8 cm. They are put at a right angle to each other with opposite poles together. The magnetic moment of the combination is
A) M/10
B) M
C) M/1.4
D) 2.8 M
Explanation
(c) Pole strength of original magnet, $m = \frac{M}{14}$
Effective distance between the poles =AB
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$M^{''} = m.2l = \frac{M}{14} \times 10 = \frac{M}{1.4}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.