# A short magnet of magnetic moment M, is placed on a straight line. The ratio of magnetic induction fields $B_1, B_3, B_3$ values on this line at points which are at distances 30 cm , 60 cm and 90 cm respectively from the center of the magnet is

$\begin {array} {1 1} (1)\;27\: : \: 3.37\: : \: 1 & \quad (2)\;37.3\: : 1\: : \: 27 \\ (3)\;27\: : \: 8\: : \: 3.37 & \quad (4)\;1\: : \: 2\: : \: 3 \end {array}$

(1) 27 : 3.37 : 1