The coefficient of linear expansion of a crystal in one direction is ${\alpha _1}$ and that in every direction perpendicular to it is ${\alpha _2}$. The coefficient of cubical expansion is

$A$ hole is drilled in a metal sheet. At $27^{\circ}C$,the diameter of the hole is $5\,cm$. When the sheet is heated to $177^{\circ}C$,the change in the diameter of the hole is $d \times 10^{-3}\,cm$. The value of $d$ will be $...........$ if the coefficient of linear expansion of the metal is $1.6 \times 10^{-5} /^{\circ}C$.

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 ..... $cm$.

$A$ copper rod of $88\; cm$ and an aluminum rod of unknown length have their increase in length independent of increase in temperature. The length of the aluminum rod is....$cm$.
$(\alpha_{Cu} = 1.7 \times 10^{-5}\; K^{-1}$ and $\alpha_{Al} = 2.2 \times 10^{-5}\; K^{-1})$

$A$ metal rod having a coefficient of linear expansion $2 \times 10^{-5} /{ }^{\circ} C$ is $0.75 \ m$ long at $45^{\circ} C$. When the temperature rises to $65^{\circ} C$,the increase in length of the rod will be: (in $mm$)

When a copper ball is heated,the largest percentage increase will occur in its