Five identical rods are joined as shown in figure. Point $A$ and $C$ are maintained at temperature $120^o C$ and $20^o C$ respectively. The temperature of junction $B$ will be....... $^oC$
$100$
$80$
$70$
$0$
$Assertion :$ Two thin blankets put together are warmer than a single blanket of double the thickness.
$Reason :$ Thickness increases because of air layer enclosed between the two blankets.
In a steady state, the temperature at the end $A$ and $B$ of $20\,cm$ long rod $AB$ are $100\,^oC$ and $0\,^oC$ respectively. The temperature of a point $9\,cm$ from $A$ is....... $^oC$
Woollen clothes are used in winter season because woolen clothes
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 ...... $^oC$
The only possibility of heat flow in a thermos flask is through its cork which is $75 cm^2$ in area and $5 cm$ thick. Its thermal conductivity is $0.0075 cal/cmsec^oC$. The outside temperature is$ 40^oC$ and latent heat of ice is $80 cal g^{-1}$. Time taken by $500 g$ of ice at $0^oC$ in the flask to melt into water at $0^oC$ is ....... $hr$