A cubical block of iron, 5 cm on each side is floating in mercury taken in a vessel. What is the height of the block above mercury level.

Explanation

From the law of floatation
`V_(b)rho_(b)=V_("in")rho_(L)`
`:.(5)^(3)xx(7.2)=(5^(2)xx(13.6)`
`:.x=2.65cm`
Then the height of the block above mercury level
`=5cm-x=2.35cm`