A black body is at a temperature $300 K$ . It emits energy at a rate, which is proportional to
A$300$
B${(300)^2}$
C${(300)^3}$
D${(300)^4}$
AIIMS 2002, Easy
Download our app for free and get started
D${(300)^4}$
d (d) Temperature of a black body $\mathrm{T}=300 \mathrm{K} .$ Stefan's law of radiation states that rate of energy emitted per unit area by the black body
$E \propto T^{4} \propto(300)^{4}$
Download our app
and get started for free
Experience the future of education. Simply download our apps or reach out to us for more information. Let's shape the future of learning together!No signup needed.*
A sphere and a cube of same material and same volume are heated upto same temperature and allowed to cool in the same surroundings. The ratio of the amounts of radiations emitted will be
A copper rod $2\,m$ long has a circular cross-section of radius $1\, cm$. One end is kept at $100^o\,C$ and the other at $0^o\,C$ and the surface is covered by nonconducting material to check the heat losses through the surface. The thermal resistance of the bar in degree kelvin per watt is (Take thermal conductivity $K = 401\, W/m-K$ of copper):-
A body takes $T$ minutes to cool from ${62^o}C$ to ${61^o}C$ when the surrounding temperature is ${30^o}C$. The time taken by the body to cool from ${70^o}$ to $({A_1}\,{\rm{and }}{A_{\rm{2}}})$ is
Four rods of identical cross-sectional area and made from the same metal form the sides of square. The temperature of two diagonally opposite points and $T$ and $\sqrt 2 $ $T$ respective in the steady state. Assuming that only heat conduction takes place, what will be the temperature difference between other two points
The sun radiates electromagnetic energy at the rate of $3.9 \times 10^{26}\,W$. It's radius is $6.96 \times 10^8\,m$. The intensity of sun light at the solar surface will be (in $W/m^2$)
Three rods made of the same material and having same cross-sectional area but different lengths $10\,\,cm$, $\,\,20 cm$ and $30\,\,cm$ are joined as shown. The temperature of the joint is ....... $^oC$
The black body spectrum of an object $O _1$ is such that its radiant intensity (i.e. intensity per unit wavelength interval) is maximum at a wavelength of $200\,nm$. Another object $O _2$ has the maximum radiant intensity at $600\,nm$. The ratio of power emitted per unit area by source $O _1$ to that of source $O _2$ is