The magnetic moment of a bar magnet 'A' and its length are twice that of another bar magnet 'B'. Arrange the following steps in sequential order to find the ratio of their pole strengths.
(a) Write the given values of magnet moment (M) and magnetic length (2l) of the bar magnets A and B as `M_(B)=2M_(A)` and `2l_(B)=2(2l_(A))`
(b) Write the expression for pole strength (m) for each magnet using m`=M/(2l)`
(c) Divide the two expression to get the ratio of `m_(A)` to `m_(B)`

Options

A. bac
B. acb
C. bca
D. abc

Answer

D

Explanation

(a) Write the given values of magnet moment (M) and length (l) of the bar magnets A and B as `M_(B)=2M_(A)` and `2l_(B)=2(2l_(A))`(a) .
(b) Write the expression for pole strength (m) for each magnet using m`=M/(2l) (b)`.
(c) Dividing the two expression to get the ratio of `m_(A)` to `m_(B)` (c)