Thermal Properties of Matter

The plots of intensity against wavelength for three black bodies at temperatures $T_1$, $T_2$ and $T_3$ are as shown. The wavelengths are such that

A cylindrical rod with one end in a steam chamber and the other end in ice results in melting of $0.1$ gram of ice per second. If the rod is replaced by another with half the length and double the radius of the first,…

The thermal conduction rate '$P_{cond}$' of a slab is given by $P_{cond} = \dfrac{kA(T_1 - T_2)}{x}$, where ' $x$ ' is the thickness of the slab and 'A' is the area . The term that represents thermal resistance ' $R_T$'

If the temperature of $5$ kg mass of a material of a specific heat capacity $200$ J/kg $^\circ$C rises from the $30^\circ$C to $40^\circ$C. The heat received is

A resistance thermometer has resistance $95\ \Omega$ at the ice point and $140\ \Omega$ at the steam point. The resistance obtained if the actual temperature is $30^\circ\text{C}$ is

A spherical blackbody of radius $10\ m$ is maintained at a temperature $T$, radiating power $P$ with a peak emission wavelength $5000\ \AA$. If the body is compressed uniformly such that its radius becomes $R/2$, while…

Three spheres P, Q and R, having radii of 2 m, 3 m and 4 m respectively, are coated with lamp-black on their outer surfaces. The wavelengths corresponding to maximum intensity are 200 nm, 300 nm and 400 nm respectively.…

A metal sphere cools at a rate of $2^\circ\text{C/min}$ when the temperature is $80^\circ\text{C}$. If the temperature of the surroundings is $30^\circ\text{C}$, then the rate of cooling when its temperature is…

If the radiant heat absorbed by the body is $75\%$ of the incident heat and if the coefficient of the reflection is $0.15$, then the coefficient of transmission is

Coefficient of linear expansion of brass and steel rods are $\alpha_1$ and $\alpha_2$. Lengths of brass and steel rod are $l_1$ and $l_2$ respectively. Though the temperature of brass and steel is increased, $(l_2 -…

The rate of dissipation of the heat by a black body at temperature $T$ is $Q$. The rate of dissipation of heat by ordinary body of the same area at temperature $3T$ and having emissivity $0.25$, will be nearly

A metal sphere cools from $80^\circ\text{C}$ to $60^\circ\text{C}$ in 10 minute. The time taken (in minute) by it to cool from $60^\circ\text{C}$ to $40^\circ\text{C}$ if the room temperature is $30^\circ\text{C}$, is