A black body radiates energy at the rate of $E$ $W/m^2$ at a high temperature $TK$ . When the temperature is reduced to $\frac{T}{2}K$, the radiant energy will be
Medium
Download our app for free and get started
(a) $E \propto {T^4} \Rightarrow \frac{{{E_1}}}{{{E_2}}} = \frac{{{T^4}}}{{{T^4}}} \times {2^4} \Rightarrow {E_2} = \frac{E}{{16}}$
Download our appand 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.*
Similar Questions
- 1A cup of coffee cools from $90^{\circ} \mathrm{C}$ to $80^{\circ} \mathrm{C}$ in $\mathrm{t}$ minutes, when the room temperature is $20^{\circ} \mathrm{C}$. The time taken by a similar cup of coffee to cool from $80^{\circ} \mathrm{C}$ to $60^{\circ} \mathrm{C}$ at a room temperature same at $20^{\circ} \mathrm{C}$ is :View Solution
- 2A solid sphere of radius $R$ and a hollow sphere of inner radius $r$ and outer radius $R$ made of copper are heated to the same temperature and are allowed to cool in the same environment. Then, choose the $CORRECT$ statementView Solution
- 3The ratio of energy of emitted radiation of a black body at ${27^o}C$ and ${927^o}C$ isView Solution
- 4Two bottles $A$ and $B$ have radii $R_{A}$ and $R_{B}$ and heights $h_{A}$ and $h_{B}$ respectively, with $R_{B}=2 R_{A}$ and $h_{B}=2 h_{A}$. These are filled with hot water at $60^{\circ} C$. Consider that heat loss for the bottles takes place only from side surfaces. If the time, the water takes to cool down to $50^{\circ} C$ is $t_{A}$ and $t_{B}$ for bottles $A$ and $B$, respectively. Then, $t_{A}$ and $t_{B}$ are best related asView Solution
- 5Wein's constant is $2892 \times {10^{ - 6}}$$MKS$ unit and the value of ${\lambda _m}$ from moon is $14.46$ microns. What is the surface temperature of moon ...... $K$View Solution
- 6A sphere of density $\rho $ , specific heat capacity $c$ and radius $r$ is hung by a thermally insulating thread in an enclosure which is kept at a lower temperature than the sphere. The temperature of the sphere starts to drop at a rate which depends upon the temperature difference between the sphere and the enclosure and the nature of the surface of sphere and is proportional toView Solution
- 7In a certain planetary system, it is observed that one of the celestial bodies having a surface temperature of $200 \;K$, emits radiation of maximum intensity near the wavelength $12\; \mu m$. The surface temperature (in $K$) of a nearby star which emits light of maximum intensity at a wavelength $\lambda= 4800\;\mathring A$ isView Solution
- 8A sphere, a cube and a disc all of the same material, quality and volume are heated to $600\,^oC$ and left in air. Which of these will have the lowest rate of cooling ?View Solution
- 9A rod $C D$ of thermal resistance $10.0\; {KW}^{-1}$ is joined at the middle of an identical rod ${AB}$ as shown in figure, The end $A, B$ and $D$ are maintained at $200^{\circ} {C}, 100^{\circ} {C}$ and $125^{\circ} {C}$ respectively. The heat current in ${CD}$ is ${P}$ watt. The value of ${P}$ is ... .View Solution
- 10Two sphere of radius $R_1$ and $R_2$ have densities ${\rho _1}$ and ${\rho _2}$ and specific heat $S_1$ and $S_2$ if they are heated to the same temperature the ratio of their rates of falling temperature will beView Solution