A block of wood is floating on water at $0^{\circ} C$ with volume $V_0$ above water. When the temperature of water increases from $0$ to $10^{\circ} C$, the change in the volume of the block that is above water is best described schematically by the graph.

At $40\,^oC$, a brass wire of $1\, mm$ is hung from the ceiling. A small mass, $M$ is hung from the free end of the wire. When the wire is cooled down from $40\,^oC$ to $20\,^oC$ it regains its original length of $0.2\, m$. The value of $M$ is close to ……..$kg$ (Coefficient of linear expansion and Young's modulus of brass are $10^{-5}/^oC$ and $10^{11}\, N/m^2$, respectively; $g = 10\, ms^{-2}$)

Each side of a box made of metal sheet in cubic shape is $'a'$ at room temperature $'T'$, the coefficient of linear expansion of the metal sheet is $^{\prime} \alpha^{\prime}$. The metal sheet is heated uniformly, by a small temperature $\Delta T$, so that its new temperature is $T +\Delta T$. Calculate the increase in the volume of the metal box.

''Anomalous expansion of water is blessing for living organisms in water''. Explain this statement. Explain Anomalous expansion of water.

In a vertical $U-$tube containing a liquid, the two arms are maintained at different temperatures ${t_1}$ and ${t_2}$. The liquid columns in the two arms have heights ${l_1}$ and ${l_2}$ respectively. The coefficient of volume expansion of the liquid is equal to