$A$ black body at a temperature of $3000 \ K$ cools down. The wavelength corresponding to maximum energy density shifts by $\Delta \lambda = 9 \ \mu m$. What is the new temperature of the black body (in $K$)? (Given $b = 3 \times 10^{-3} \ m \cdot K$)

The following graph represents the radiant power versus wavelength of a black body. The area under the curve represents:

$A$ black body has a maximum wavelength $\lambda_m$ at $2000\,K$. Its corresponding wavelength at $3000\,K$ will be:

The maximum energy in the thermal radiation from a hot source occurs at a wavelength of $11 \times 10^{-5} \ cm$. According to Wien's law, the temperature of the source (on Kelvin scale) will be $n$ times the temperature of another source (on Kelvin scale) for which the wavelength at maximum energy is $5.5 \times 10^{-5} \ cm$. The value of $n$ is

The emissive power of a sphere of area $0.04 \,m^2$ is $0.7 \,kcal \,s^{-1} \,m^{-2}$. The amount of heat radiated in $20 \,s$ is: (in $\,kcal$)

At a temperature of $2000 \; K$,the maximum energy of a black body is emitted at a wavelength of $14 \; \mu m$. When its temperature is reduced to $1000 \; K$,the wavelength corresponding to the maximum energy emitted is ....... $\mu m$.