When red glass is heated in a dark room,it will appear:

Which of the following statements does not hold good for thermal radiation?

When we enter an air-conditioned room,we feel cold. This can be explained by:

The velocity of heat radiation in vacuum is

If the transmission power of a surface is $\frac{1}{9}$ and the reflective power is $\frac{1}{6}$,then what is its absorptive power?

Nearly $10 \%$ of the power of a $110\,W$ light bulb is converted to visible radiation. The change in average intensities of visible radiation,at a distance of $1\,m$ from the bulb to a distance of $5\,m$ is $a \times 10^{-2}\,W/m^2$. The value of '$a$' will be.