The top of insulated cylindrical container is covered by a disc having emissivity $0.6$ and thickness $1\, cm$. The temperature is maintained by circulating oil as shown in figure. If temperature of upper surface of disc is $127^o C$ and temperature of surrounding is $27^o C$, then the radiation loss to the surroundings will be (Take $\sigma = \frac{{17}}{3} \times {10^{ - 8}}W/{m^2}{K^4})$
Medium
Download our app for free and get started
(a) Rate of heat loss per unit area due to radiation i.e. emissive power $e = \varepsilon \sigma ({T^4} - T_0^4)$
$ = 0.6 \times \frac{{17}}{3} \times {10^{ - 8}} \times \,[{(400)^4} - {(300)^4}]$
$ = 3.4 \times {10^{ - 8}} \times (175 \times {10^8}) = 3.4 \times 175 = 595\,J/{m^2} \times \sec $
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
- 1In a steady state of thermal conduction, temperature of the ends $A$ and $B$ of a $20\, cm$ long rod are ${100^o}C$ and ${0^o}C$ respectively. What will be the temperature of the rod at a point at a distance of $6$ cm from the end $A$ of the rod....... $^oC$View Solution
- 2The adjoining diagram shows the spectral energy density distribution ${E_\lambda }$of a black body at two different temperatures. If the areas under the curves are in the ratio $16 : 1$ , the value of temperature $T$ is ........ $K$View Solution
- 3The top of a lake gets frozen at a place where the surrounding air is at a temperature of $-20\,^oC$. ThenView Solution
- 4For the shown figure, calculate the equivalent thermal resistance if the bricks made of the same material of conductivity $K$View Solution
- 5Three discs $A, B$ and $C$ having radii $2\; m, 4\;m,$ and $6 \;m$, respectively are coated with carbon black on their outer surfaces. The wavelengths corresponding to maximum intensity are $300\; nm, 400\; nm$ and $500\; nm$, respectively. The power radiated by them are $Q_A,Q_B$ and $Q_C$ respectively.View Solution
- 6The coefficient of linear expansion of brass and steel are ${\alpha _1}$ and ${\alpha _2}$. If we take a brass rod of length ${l_1}$ and steel rod of length ${l_2}$ at $0°C$, their difference in length $({l_2} - {l_1})$ will remain the same at a temperature ifView Solution
- 7A particular star (assuming it as a black body) has a surface temperature of about $5 \times {10^4}K.$The wavelength in nanometers at which its radiation becomes maximum is $(b = 0.0029 mK)$View Solution
- 8Two metal cubes $A$ and $B$ of same size are arranged as shown in the figure. The extreme ends of the combination are maintained at the indicated temperatures. The arrangement is thermally insulated. The coefficients of thermal conductivity of $A$ and $B$ are $300\;W/m{\;^o}C$ and $200\;W/m{\;^o}C$, respectively. After steady state is reached, the temperature of the interface will be...... $^oC$View Solution
- 9A 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
- 10View SolutionIn rainy season, on a clear night the black seat of a bicycle becomes wet because