Which of the following circular rods. (given radius $ r$ and length $l$ ) each made of the same material as whose ends are maintained at the same temperature will conduct most heat

Find Temperature difference between $B$ and $C$ ? (All rods are identical)

The length of the two rods made up of the same metal and having the same area of cross-section are $0.6 m$ and $0.8 m$ respectively. The temperature between the ends of first rod is ${90^o}C$ and ${60^o}C$ and that for the other rod is $150^oC$ and ${110^o}C$. For which rod the rate of conduction will be greater

Three rods $AB, BC$ and $AC$ having thermal resistances of $10\, units, \,10 \,units$ and $20 \,units,$ respectively, are connected as shown in the figure. Ends $A$ and $C$ are maintained at constant temperatures of $100^o C$ and $0^o C,$ respectively. The rate at which the heat is crossing junction $B$ is   …….. $ \mathrm{units}$

Consider a compound slab consisting of two different materials having equal thickness and thermal conductivities $  K$ and $2K$ respectively. The equivalent thermal conductivity of the slab is