A long straight wire carrying current of $25\;A$ rests on a table as shown in the figure. Another wire $PQ$ of length $1\;m$ mass $2.5\;g$ carries the same current but in the opposite direction. the wire $PQ$ is free opposite direction. The wire PQ is free to slide up and down . To what height will PQ rise ?

Question

$\begin{array}{1 1} 51\;cm \\ 5.1\;cm \\ 0.51\;cm \\ 0.051\;cm \end{array}$