Two metal strips that constitute a thermostat must necessarily differ in their

The focal length of a spherical mirror made of steel is $150 \,cm$. If the temperature of the mirror increases by $200 \,K$, its focal length becomes (coefficient of linear expansion of steel $\alpha = 12 \times 10^{-6} \,^{\circ}C^{-1}$). (in $\,cm$)

The ratio of linear expansion coefficient,area expansion coefficient,and volume expansion coefficient is ...............

$A$ clock with an iron pendulum keeps correct time at $15^{\circ} C$. If the room temperature is $20^{\circ} C$,the error in seconds per day will be nearly (coefficient of linear expansion of iron is $\alpha = 1.2 \times 10^{-5} /{ }^{\circ} C$) (in $s$)

$A$ cuboid $ABCDEFGH$ is anisotropic with $\alpha_x = 1 \times 10^{-5} /^{\circ}C$,$\alpha_y = 2 \times 10^{-5} /^{\circ}C$,$\alpha_z = 3 \times 10^{-5} /^{\circ}C$. The coefficient of superficial expansion of the faces can be:

$A$ steel tape measures the length of a copper rod as $90 \ cm$ when both are at $10 \ ^oC$. What length (in $cm$) would the tape read for the length of the rod when both are at $30 \ ^oC$? $[\alpha_{st} = 1.2 \times 10^{-5} / ^oC$ and $\alpha_{cu} = 1.7 \times 10^{-5} / ^oC]$