An iron rod has a length of $10 \ cm$ at $20^{\circ}C$. What will be the change in length of the iron rod at $19^{\circ}C$? (Given for iron,$\alpha = 11 \times 10^{-6} \ ^{\circ}C^{-1}$)

When a copper ball is heated,which of the following will show the maximum percentage increase?

On what value does the coefficient of linear expansion $\alpha_l$ depend? Write its unit.

$A$ piece of metal has a weight of $49 \ gm$ in air and $39 \ gm$ in a liquid of density $1.2 \times 10^3 \ kg/m^3$ kept at $32^{\circ}C$. When the temperature of the liquid is raised to $42^{\circ}C$,the metal piece has a weight of $40 \ gm$. If the density of the liquid at $42^{\circ}C$ is $1.0 \times 10^3 \ kg/m^3$,then the coefficient of linear expansion of the metal is:

Two rods,one made of aluminium and the other made of steel,having initial lengths $l_1$ and $l_2$ respectively,are connected together to form a single rod of length $(l_1 + l_2)$. The coefficients of linear expansion for aluminium and steel are $\alpha_1$ and $\alpha_2$ respectively. If the length of each rod increases by the same amount when their temperature is raised by $t^oC$,then the ratio $l_1/(l_1 + l_2)$ is:

If the temperature of a rod is increased in such a way that no linear expansion occurs,then the stress developed in the rod does not depend on .......