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/(14)`
D. 2.8 M

Answer

C

Explanation

Pole strength of original magnet `m=M/(14),M_1=M/(14)xx6 and M_2=M/(14)xx8`
Magnetic moment of the conmbination = `M=sqrt(M_1^2+M_2^2)=M/(14)sqrt(6^2+8^2)=(10M)/(14)=M/(1.4)`