Thermal Properties of Matter

A black body is at a temperature of $\text{5760}\text{K.}$ The energy of radiation emitted by the body at wavelength $\text{250}\text{nm}$ is $U_{1}$, at wavelength $\text{500}\text{nm}$ is $U_{2}$ and that at…

A spherical black body with a radius of $12\mathrm{cm}$ radiates $450W$ power at $500K$. If the radius were halved and the temperature doubled, the power radiated in watt would be

Threerods of identical cross-section and length are made of three different materials of thermal conductivity$K_{1},K_{2}$and$K_{3}$, respectively. They are joined together at their ends to make a long rod (see figure).…

If $K_{1}$and $K_{2}$ are the thermal conductivities $L_{1}$ and $L_{2}$ are the lengths and $A_{1}$ and $A_{2}$ are the cross sectional areas of steel and copper rods respectively such that…

A black coloured solid sphere of radius $R$ and mass $M$is inside a cavity with a vacuum inside. The walls of the cavity are maintained at temperature $T_{0}$. The initial temperature of the sphere is $3T_{0}$. If the…

Two materials having coefficients of thermal conductivity $3K$ and $K$ and thickness $d$ and $3\text{d}$ respectively, are joined to form a slab as shown in the figure. The temperatures of the outer surfaces are…

The temperature $\theta\,$ at the junction of two insulating sheets, having thermal resistances $R_{1}$ and $R_{2}$ as well as top and bottom temperatures $\theta\,_{1}$ and $\theta\,_{2}$ (as shown in figure) is given…

Temperature difference of $120^{o}C$ 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…

Two thin metallic spherical shells of radii $r_{1}$ and $r_{2}\left(r_{1}<r_{2}\right)$ are placed with their centres coinciding. A material of thermal conductivity $K$ is filled in the space between the shells. The…

An ice cube of dimensions $60\mathrm{cm}\times\,50\mathrm{cm}\times\,20\mathrm{cm}$ is placed in an insulation box of wall thickness $1\mathrm{cm}$. The box keeping the ice cube at $0^{\circ}C$ of temperature is brought…

Two metallic wires of identical dimensions are connected is series. If $\sigma\,_{1}$ and $\sigma\,_{2}$ are the conductivities of the these wires respectively, the effective conductivity of the combination is :

Three rods of Copper, Brass and Steel are welded together to form a Y-shaped structure. Area of cross-section of each rod is$4\mathrm{cm}^{2}$. End of copper rod is maintained at $100^{\circ}C$. Where as ends of brass…