Thermal Propert...

A cubical box of side $$0.20\ m$$ is constructed from $$0.012\ m$$ thick concrete panels of thermal conductivity $$K = 0.8\ W\ m^{-1} K^{-1}$$. A $$100\ W$$ heater is sealed inside the box and switched on. The temperature of air outside the box is $$20^{\circ}C$$. After a long period of time, the air temperature inside the box will be close to

Vijay performed an experiment to compare the heat conductivity of four different materials P, Q, R and S. Thumbtacks were fixed with wax on each material and then the materials were fixed to a trough containing hot water as shown in the diagram. Vijay tabulated his results as shown here.

two bars of same length and same cross-sectional area but of different thermal conductivities $$ { K }_{ 1 } $$ and $$ { K }_{ 2 } $$ are joined end to end as shown in the figure. One end of the compound bar is at temperature $$ { T }_{ 1 } $$ and the opposite end at temperature $$ { t }_{ 2 } $$ (where $$ { T }_{ 1 }>{ T }_{ 2 } $$). the temperature of the junction is 

One Kg of a diatomic gas is at a pressure of $$8\times 10^4$$N/ $$m^{2}$$. The density of the gas is $$4$$kg/ $$m^{3}$$. The energy of the gas due to its thermal motion will be

Which one of the following is not an assumption of kinetic theory of gases?

If the pressure and the volume of certain quantity of ideal gas are halved, then its temperature

Two blocks with heat capacities $$ { C }_{ 1 } $$ and $$ { C }_{ 2 } $$ are connected by a rod of length l, cross-sectional are A and heat conductivity K. Initial temperature difference between the two blocks is $$ { T }_{ 0 } $$. Assuming the entire system to be isolated from surroundings, heat capacity of the rod to be negligible. The temperature difference between the blocks as a function of time is. 

A vessel contains a mixture consisting of $${m}_{1}=7kg$$ of nitrogen $$\left( { M }_{ 1 }=28 \right) $$ and $${m}_{2}=11g$$ of carbon dioixide $$\left( { M }_{ 2 }=44 \right) $$ at temeprature $$T=300K$$ and pressure $${ P }_{ 0 }=1\quad atm$$. The density of the mixture is:

When a thermometer is taken from the melting ice to a warm liquid, the mercury level rises to $$ \\ \\ \left(\dfrac { 2}{ 5 }\right)^{ th } $$ of the distance between the lower and the upper fixed points. The temperature of liquid in K is

Heat from the sun is received by the earth through