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.
A student records the initial length $l$, change in temperature $\Delta T$ and change in length $\Delta l$ of a rod as follows :
S.No. | $l(m)$ | $\Delta T{(^o}C)$ | $\Delta l(m)$ |
$(1)$ | $2$ | $10$ | $4\times 10^{-4}$ |
$(2)$ | $1$ | $10$ | $4\times 10^{-4}$ |
$(3)$ | $2$ | $20$ | $2\times 10^{-4}$ |
$(4)$ | $3$ | $10$ | $6\times 10^{-4}$ |
If the first observation is correct, what can you say about observations $2,\,3$ and $4$.
The coefficient of linear expansion of a crystalline substance in one direction is $2 \times 10^{-4} /{ }^{\circ} C$ and in every direction perpendicular to it is $3 \times 10^{-4} /{ }^{\circ} C$. The coefficient of cubical expansion of crystal is equal to ........... $\times 10^{-4} /{ }^{\circ} C$
When a bimetallic strip is heated, it
A circular metallic disc of radius $R$ has a small circular cavity of radius $r$ as shown in figure. On heating the system
The weight of sphere in air is $50\ g$. Its weight $40\ g$ in a liquid, at temperature $20\,^o C$. When temperature increases to $70\,^o C$ , it weight becomes $45\ g$, then the ratio of densities of liquid at given two temperature is