Solar radiation emitted by the sun resembles that emitted by a black body at a temperature of $6000\,K$. Maximum intensity is emitted at wavelength of about $4800{\text{ }}\mathop {\text{A}}\limits^o $. If the sun was cooled down from $6000\,K$ to $3000\,K$, then the peak intensity would occur at a wavelength of …….. $\overset{o}{\mathop{A}}$

A black body at a high temperature $T\, K$ radiates energy at the rate $E\, watt/m^2$ ; when the temperature falls to $(T/2)\, K$ the radiated energy will be

On heating one end of a rod, the temperature of whole rod will be uniform when

The temperature of a black body reduces to half of its actual value. By what fraction will the amount of radiations given out reduce?

Three rods $A, B,$ and $C$ of thermal conductivities $K, 2K$ and $4K$, cross-sectional areas $A, 2A$ and $2A$ and lengths $2l, l$ and $l$ respectively are connected as shown in the figure. If the ends of the rods are maintained at temperatures $100\,^oC$, $50\,^oC$, and $0\,^oC$ respectively, then the temperature $\theta$ of the junction is