The equivalent inductance of two inductances is `2.4` henry when connected in parallel and `10` henry when connected in series. The difference between the two inductance is

Options

A. 2 henry
B. 3 henry
C. 4 henry
D. 5 henry

Answer

A

Explanation

`(L_1 L_2)/(L_1 + L_2) = 24 `
`L_1 + L_2 = 10`
`implies L_1 - L_2 = sqrt((L_1 + L_1)^2 - 4L_1 L_2)`
`= sqrt(10^2 - 4 xx 24)`
`= sqrt(100 - 96) = sqrt(4)`
`= 2`