Two poles seprated by 10 cm experiences a force on mN.Find the force between them when the distance is doubled and the pole strengths are doubled.

Options

A. 5mN
B. 10mN
C. 2.5mN
D. 1 mN

Answer

A

Explanation

`F_(1)=5mN,F_(2)=?`
`m'_(1)=2m_(1) and m'_(2)=2m_(2),r_(2)=2r_(1)`
`F oo(m_(1)m_(2))/(r^(2))`
`(F_(2))/(F_(1))=(m'_(1)m'_(2))/(m_(1)m_(2))((r_(1))/(r_(2)))^(2) =(2m_(1)xx2m_(2))/(m_(1)m_(2))xx((r_(1))/(2r_(1)))^(2)`
`F_(2)=F_(1)=5 mN.`