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…

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 :

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 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…

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…

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…

A block of ice of mass $120g$ at temperature $0^{\circ}C$ is put in $300g$ of water at $25^{\circ}C$. The $xg$ of ice melts as the temperature of the water reaches $0^{\circ}C$. The value of $x$ is [Use: Specific heat…

A hole is drilled in a metal sheet. At $27^{\circ}C$, the diameter of hole is $5\mathrm{cm}$. When the sheet is heated to $177^{\circ}C$, the change in the diameter of hole is $d\times\,10^{-3}\mathrm{cm}$ . The value…

The heat extracted out of $x$ gram of water initially at $50^{\circ}C$ to cool it down to $0^{\circ}C$ is sufficient to evaporate $(1000 - x)$ gram of water also initially at $50^{\circ}C$. The value of $x$ (closest…

A water heater of power $2000W$is used to heat water. The specific heat capacity of water is $4200J\mathrm{kg}^{-1}K^{-1}$. The efficiency of heater is $70%$. Time required to heat $2\mathrm{kg}$ of water from…

A unit scale is to be prepared whose length does not change with temperature and remains $20\mathrm{cm}$, using a bimetallic strip made of brass and iron each of different length. The length of both components would…

A faulty thermometer reads $5^{\circ}C$in melting ice and $95^{\circ}C$in steam. The correct temperature on absolute scale will be ______ $K$ when the faulty thermometer reads$41^{\circ}C$?