A black body has maximum wavelength ${\lambda }_{\mathrm{m}}$ at temperature $2000 \mathrm{K}$. Its corresponding wavelength at temperature $3000 \mathrm{K}$ will be

A black body emits radiations of maximum intensity at a wavelength of $5000 \stackrel{\circ }{\mathrm{A}}$, when the temperature of the body is $1227 °\mathrm{C}$. If the temperature of the body is increased by $1000 °\mathrm{C}$, the maximum intensity of emitted radiation would be observed at

A black body is at a temperature of $5760 \mathrm{K}$. The energy of radiation emitted by the body at wavelength $250 \mathrm{nm}$ is $U_1$, at wavelength $500 \mathrm{nm}$ is $U_2$ and that at $1000 \mathrm{nm}$ is $U_3$. Wien's constant, $b=2.88\times {10}^{6 } \mathrm{nm} \mathrm{K}$. Which of the following is correct? 

Three objects coloured black, grey and white can withstand hostile conditions up to $2800 °\mathrm{C}$. These objects are thrown into a furnace where each of them attains a temperature of $2000 °\mathrm{C}$. Which object will glow brightest? 

Two perfect black bodies $A_1$ and $A_2$ made out of same material have diameters $2 \mathrm{cm}$ and $16 \mathrm{cm}$ respectively. $\lambda {\text{'}}_{\max }$ and $\lambda \text{'}{\text{'}}_{\max }$ are the wavelengths corresponding to their maximum radiation of energy at a common temperature $\lambda {\text{'}}_{\max }$ and $\lambda \text{'}{\text{'}}_{\max }$ are related as 

A black rectangular surface of area $A$ emits energy $E$ per second at $27 °\mathrm{C}$. If length and breadth are reduced to $\frac{1}{3}$ of initial value and temperature is raised to $327 °\mathrm{C}$, then energy emitted per second becomes