A ball of density $0.5 \times 10^3$ is dropped from a height of $10\; m$ and then enters water . Upto what depth will the ball go inside the water before it starts raising up.
$\begin {array} {1 1} (a)\;5\;m \\ (b)\;6\;m \\ (c)\;10 \;m \\ (d)\;12\;m \end {array}$