Six wire each of cross-sectional area $A$ and length $l$ are combined as shown in the  figure. The thermal conductivities of copper and iron are $K_1$ and $K_2$ respectively.  The equivalent thermal resistance between points $A$ and $C$ is :-

A composite block is made of slabs $A, B, C, D$ and $E$ of different thermal conductivities (given in terms of a constant $K$ ) and sizes (given in terms of length, $L$ ) as shown in the figure. All slabs are of same width. Heat $'Q'$ flows only from left to right through the blocks. Then in steady state $Image$

$(A)$ heat flow through $A$ and $E$ slabs are same.

$(B)$ heat flow through slab $E$ is maximum.

$(C)$ temperature difference across slab $E$ is smallest.

$(D)$ heat flow through $C =$ heat flow through $B +$ heat flow through $D$.

Temperature difference of $120\,^oC$ is maintained between two ends of a uniform rod $AB$ of length $2L$. Another bent rod $PQ$, of same cross-section as $AB$ and length $\frac{{3L}}{2}$,  is connected across $AB$ (See figure). In steady state, temperature difference between $P$ and $Q$ will be close to .......... $^oC$

A long metallic bar is carrying heat from one of its ends to the other end under steady-state. The variation of temperature $\theta$ along the length $x$ of the bar from its hot end is best described by which of the following figures?

Find effective thermal resistance between $A$ & $B$ of cube made up of $12$ rods of same dimensions and shown given thermal conductivity. [ $l =$ length of rod, $a =$ cross section area of rod]

Two bars of thermal conductivities $K$ and $3K$ and lengths $1\,\, cm$ and $2\,\, cm$ respectively have equal cross-sectional area, they are joined lengths wise as shown in the figure. If the temperature at the ends of this composite bar is $0\,^oC$ and $100\,^oC$ respectively (see figure), then the temperature $\varphi $ of the interface is......... $^oC$