The quantity of heat which crosses unit area of a metal plate during conduction depends upon
The density of the metal
The temperature gradient perpendicular to the area
The temperature to which the metal is heated
The area of the metal plate
A copper rod and a steel rod of equal cross-sections and lengths $(L)$ are joined side by side and connected between two heat baths as shown in the figure
If heat flows through them from $x = 0$ to $x = 2L$ at a steady rate and conductivities of the metals are $K_{cu}$ and $K_{steel}$ $(K_{cu} > K_{steel}),$ then the temperature varies as (convection and radiation are negligible)
The ratio of thermal conductivity of two rods of different material is $5 : 4$ . The two rods of same area of cross-section and same thermal resistance will have the lengths in the ratio
The temperature gradient in a rod of $0.5 m$ long is ${80^o}C/m$. If the temperature of hotter end of the rod is ${30^o}C$, then the temperature of the cooler end is ...... $^oC$
Two rectangular blocks, having indentical dimensions, can be arranged either in configuration $I$ or in configuration $II$ as shown in the figure, On of the blocks has thermal conductivity $k$ and the other $2 \ k$. The temperature difference between the ends along the $x$-axis is the same in both the configurations. It takes $9\ s$ to transport a certain amount of heat from the hot end to the cold end in the configuration $I$. The time to transport the same amount of heat in the configuration $II$ is :
Temperature of water at the surface of lake is $ - {20^o}C$ Then temperature of water just below the lower surface of ice layer is ...... $^oC$