If the volume of a block of metal changes by $0.12 \%$ when it is heated thrugh $20^oC$, the coefficient of linear expansion (in $^oC^{-1}$) of the metal is
The value of coefficient of volume expansion of glycerin is $5 \times 10^{-4}k^{-1} .$ The fractional change in the density of glycerin for a rise of $40^o C$ in its temperature, is
Why the density is changed of solid substances by increase in temperature ?
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
A steel rod with ${y}=2.0 \times 10^{11} \,{Nm}^{-2}$ and $\alpha=10^{-5}{ }^{\circ} {C}^{-1}$ of length $4\, {m}$ and area of cross-section $10\, {cm}^{2}$ is heated from $0^{\circ} {C}$ to $400^{\circ} {C}$ without being allowed to extend. The tension produced in the rod is ${x} \times 10^{5} \, {N}$ where the value of ${x}$ is ....... .