Three rods $A, B,$ and $C$ of thermal conductivities $K, 2K$ and $4K$, cross-sectional areas $A, 2A$ and $2A$ and lengths $2l, l$ and $l$ respectively are connected as shown in the figure. If the ends of the rods are maintained at temperatures $100\,^oC$, $50\,^oC$, and $0\,^oC$ respectively, then the temperature $\theta$ of the junction is
$\frac{{300}}{7}\,^oC$
$\frac{{300}}{13}\,^oC$
$\frac{{200}}{7}\,^oC$
$\frac{{200}}{13}\,^oC$
A body cools from $62\,^oC$ to $50\,^oC$ in $10\, minutes$ and to $42\,^oC$ in the next $10\, minutes$. The temperature of the surrounding is ........ $^oC$
Heat is conducted across a composite block of two slabs of thickness $d$ and $2d$. Their thermal conductivities are $2k$ and $k$ respectively. All the heat entering the face $AB$ leaves from the face $CD$. The temperature in $^o C$ of the junction $EF$ of the two slabs is :
Two rods $A$ and $B$ of same cross-sectional are $A$ and length $l$ connected in series between a source $(T_1 = 100^o C)$ and a sink $(T_2 = 0^o C)$ as shown in figure. The rod is laterally insulated The ratio of the thermal resistance of the rod is
Two rods of same length and material transfer a given amount of heat in $12\,s,$ when they are joined end to end. But when they are joined lengthwise, then they will transfer same heat in same conditions in .......... $\sec$
In a composite rod, when two rods of different lengths $l_1$ and $l_2$ and of the same cross-sectional area are joined from end to end then if $K$ is the effective coefficient of thermal conductivity, the value of $(l_1 + l_2)/K$ is