Shown below are the black body radiation curves at temperatures $T_1$ and $T_2$ $(T_2 > T_1)$. Which of the following plots is correct?

There is a black spot on a body. If the body is heated and carried into a dark room,then it glows more than the rest of the body. This can be explained on the basis of:

$A$ thermopile is used for:

Consider black body radiation in a cubical box at absolute temperature $T$. If the length of each side of the box is doubled and the temperature of the walls of the box and that of the radiation is halved, then the total energy

Inside a closed furnace held at a temperature of $400\, K,$ we have a black body. $A$ hole of area $10\, cm^2$ is opened in the furnace so that sunlight starts falling on the black body. The intensity of sunlight is $2000\, W/m^2.$ In the steady state:

Which of the following statements is correct?