If two identical bar magnets, each of length I, pole strength m and magnetic moment M are placed perpendicular to each other with their unlike poles in contact, the magnetic moment of the combination is

Options

A. `M/sqrt2`
B. `lm(sqrt2)`
C. `2lm(sqrt2)`
D. `2 m`

Answer

B

Explanation

When two magnets are placed perpendicular to each other resultant pole strength is,
`M^(1)=sqrt(M_(1)^(2)+M_(2)^(2)`
Here, `M_(1)=M_(2)=m`
`M^(1)=sqrt2`
Magnetic moment of the system is,
`M=M^(1)l=sqrt2lm`