Question

A solid cylinder of mass $m$ is floating in water at $2^{\circ }C$. If the water is heated upto $4^{\circ }C$ ( water has highest density), then from floating condition, cylinder

• A. will rise
• B. will sink
• C. will remain at same depth
• D. cannot say

Answer 1

The correct option is A will rise


From given, for floating
$\Rightarrow mg=F_{Buoyancy}$
$\Rightarrow mg=A{l}_1{\rho }_{1}g$
$\Rightarrow m=A{l}_1{\rho }_1$
For $2^{\circ }C,m=A{l}_1{\rho }_1$ and for $4^{\circ }C,m=A{l}_2{\rho }_2$
${\rho }_2>{\rho }_1$ $(\because \rho at{4}^{\circ }C$ is maximum)
$\therefore l_2<l_1$
So the cylinder will rise.