A magnet of length 14cm and magnetic moment M is broken into two parts of lengths 6 cm and 8cm. They are put at right angle to each other with opposite poles together. The magnetic moments of the combinaation is

Options

A. `(M)/(10)`
B. M
C. `(M)/(1.4)`
D. 2.8M

Answer

C

Explanation

Pole strength of original magnet `m=(M)/(14), :.M_(1)=(M)/(14) xx 6 and M_(2) = (M)/(14) xx 8`
Magnetic moment of the combination `M= sqrt(M_(1)^(2) +M_(2)^(2)) =(M)/(14) sqrt(6^(2) +8^(2)) =(10m)/(14) =(M)/(1.4) `