Three long straight and parallel wires carrying currents are arranged as shown in the figure. The wire `C` which carreis a current of `5.0 amp` is so placed that it experiences no force. The distance of wire `C` from `D` is then

Options

A. 9 cm
B. 7 cm
C. 5 cm
D. 3 cm

Answer

A

Explanation

For no force on wire `C`, force on wire `C` due to wire `D` = force on wire `C` due to wire `B`
`implies (mu_(0))/(4pi) xx (2xx15xx5)/(x) xx l = (mu_(0))/(4pi) xx (2xx5xx10)/((15 - x)) xx l`
`implies x = 9 cm`