$A$ thin copper wire of length $L$ increases in length by $1\%$ when heated from temperature $T_1$ to $T_2$. What is the percentage change in area when a thin copper plate having dimensions $2L \times L$ is heated from $T_1$ to $T_2$?

An iron rod of length $10 \ m$ is heated from $0 \ ^{\circ}C$ to $100 \ ^{\circ}C$. If the coefficient of linear expansion of iron is $10 \times 10^{-6} \ ^{\circ}C^{-1}$,then the increase in the length of the rod is ..... $cm$.

An iron bar of length $10\, m$ is heated from $0^{\circ}C$ to $100^{\circ}C$. If the coefficient of linear thermal expansion of iron is $10 \times 10^{-6} {^{\circ}C^{-1}}$,the increase in the length of the bar is .......... $cm$.

As shown in the figure,an equilateral triangle $ABC$ is formed by joining three rods of equal lengths $l$. $D$ is the midpoint of $AB$. The coefficient of linear expansion of the material of rod $AB$ is $\alpha_1$ and that of rods $AC$ and $BC$ is $\alpha_2$. If the length $DC$ remains constant for small changes in temperature,then:

On what does the value of the coefficient of linear expansion depend?

The volume of a metal block increases by $0.225 \%$ when its temperature is increased by $30^{\circ} C$. Hence,the coefficient of linear expansion of the material of the metal block is