If a bar magnet of pole strength m and magnetic moment M is cut equally 5 times parallel to its axis and again 3 times perpendicular to its axis, then the pole strength and magnetic moment of each piece are respectively.

Options

A. `m/20,M/4`
B. `m/5,M/20`
C. `m/6,M/24`
D. `m/5,M/24`

Answer

C

Explanation

Polo strength = m and magnetic =M
When magnet is cut 5 times number of pieces n=6
Pole strength `m^(1)=m/n=m/6`
When magnet is cut 3 times perpendicular to axis
number of pieces n=4, then length `2l^(1)=(2l)/(n)=(2l)/(4)`
therefore pole strength `m^(1)=m/6`
Magnetic moment `M=((m)/(6))((2l)/(4)) =m/24`