Question

Two magnetic poles, one of which is four times stronger than the other, exert a force of `10gf` on each other, when placed at a distance of `10cm` in air. Find the strength of each pole.

Answer 1

Here, `m_1=m`, `m_2=4m`,
`r=10cm=0*1m`, `F=10gf=10^-2xx9*8N`
As `F=(mu_0)/(4pi)(m_1m_2)/(r^2)`
`:. 9*8xx10^-2=10^-7(m(4m))/((0*1)^2)`
`4m^2=9800`, `m^2=2450`.
`m=sqrt(2450)=49*5Am`
`:.` Strength of one pole`=49.5Am`
and strength of other pole `=4m=4xx49*5`
`=198Am`