The distribution of relative intensity $I (\lambda )$ of blackbody radiation from a solid object versus the wavelength $\lambda $ is shown in the figure. If the Wien displacement law constant is $2.9 × 10^{-3}\ mK$ , what is the approximate temperature of the object ……. $K$.

A body cools in a surrounding which is at a constant temperature of $\theta _0$ . Assuming that it obeys Newton's law of cooling, its temperature $\theta $ is plotted against time $t$ . Tangents are drawn to the curve at the points $A(\theta  = \theta _1)$ and $B(\theta = \theta _2)$ . These tangents meet the time-axis at angles $\alpha _1$ and $\alpha _2$ as shown in the graph then

Two identical metal wires of thermal conductivities $K _{1}$ and $K _{2}$ respectively are connected in series. The effective thermal conductivity of the combination is

The rate of emission of radiation of a black body at $273^o C$ is $E$, then the rate of emission of radiation of this body at $0^o C$ will be

Two identical rods of copper and iron are coated with wax uniformly. When one end of each is kept at temperature of boiling water, the length upto which wax melts are $8.4\, cm$ amd $4.2\, cm$, respectively. If thermal conductivity of copper is $0.92$, then thermal conductivity of iron is