Two metal cubes with $3 \mathrm{cm}$ edges of copper and aluminum are arranged as shown in the figure. Find,

(a) The total thermal current from one reservoir to the other.

(b) The ratio of the thermal current carried by the copper cube to that carried by the aluminum cube. The thermal conductivity of copper is $60 \mathrm{W} {\mathrm{m}}^{-1} {\mathrm{K}}^{-1}$ and that of aluminum is$40 \mathrm{W} {\mathrm{m}}^{-1} {\mathrm{K}}^{-1}$.

Three conducting rods of same material and cross-section are shown in figure. The temperature of $A\text{,} D \text{and} C$ are maintained at $20°\mathrm{C}, 90°\mathrm{C} \text{and} 0°\mathrm{C}$. Find the ratio of lengths $BD \text{and} BC$ if there is no heat flow in $AB$.

Which of the curves in the figure represents the relation between Celsius and Fahrenheit temperature?

The graph $AB$ shown in figure is a plot of temperature of a body in degree Celsius and degree Fahrenheit. Then,