The density of a substance at $0^{\circ}C$ is $10 \, g/cm^3$ and at $100^{\circ}C$,its density is $9.7 \, g/cm^3$. The coefficient of linear expansion of the substance is:

$A$ clock pendulum made of invar has a period of $0.5 \, s$ at $20^{\circ} C$. If the clock is used in a climate where the temperature averages to $30^{\circ} C$, how much time does the clock lose in each oscillation? (For invar, $\alpha = 9 \times 10^{-7} /{ }^{\circ} C$, $g = \text{constant}$)

The coefficient of apparent expansion of mercury in a glass vessel is $153 \times 10^{-6} \, ^{\circ}C^{-1}$ and in a steel vessel is $144 \times 10^{-6} \, ^{\circ}C^{-1}$. If $\alpha$ for steel is $12 \times 10^{-6} \, ^{\circ}C^{-1}$,then that of glass is:

Two rods,one of aluminum and another of steel,have initial lengths $l_1$ and $l_2$ respectively. They are joined together to form a single rod of length $(l_1 + l_2)$. If the coefficients of linear expansion for aluminum and steel are $\alpha_a$ and $\alpha_s$ respectively,and the increase in length for both rods is the same when the temperature of both is increased by $t \ ^\circ C$,then $\frac{l_1}{l_1 + l_2} = \dots$

$A$ bimetallic strip is formed out of two identical strips,one of copper and the other of brass. The coefficients of linear expansion of the two metals are $\alpha_C$ and $\alpha_B$. On heating,the temperature of the strip increases by $\Delta T$ and the strip bends to form an arc of radius of curvature $R$. Then $R$ is:

$A$ steel rod at $25^{\circ} C$ is observed to be $1 \ m$ long when measured by another metal scale which is correct at $0^{\circ} C$. The exact length of the steel rod at $0^{\circ} C$ is $(\alpha_{\text{steel}} = 12 \times 10^{-6} \ ^{\circ} C^{-1}, \alpha_{\text{metal}} = 20 \times 10^{-6} \ ^{\circ} C^{-1})$. (in $m$)