The area of a hole of heat furnace is ${10^{ - 4}}{m^2}$. It radiates $1.58 \times {10^5}$ calories of heat per hour. If the emissivity of the furnace is $0.80$ , then its temperature is....... $K$
Medium
Download our app for free and get started
(c) According to Stefen’s law $E = \sigma \,\varepsilon A{T^4}$
==>$\frac{{1.58 \times {{10}^5} \times 4.2}}{{60 \times 60}} = 5.6 \times {10^{ - 8}} \times {10^{ - 4}} \times 0.8 \times {T^4}$
$T \approx 2500\,K$
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
- 1View SolutionWhich of the following factors affect the thermal conductivity of a rod?
- 2The two ends of a rod of length $L$ and a uniform cross-sectional area $A$ are kept at two temperatures $T_1$ and $T_2 (T_1 > T_2)$. The rate of heat transfer,$\frac{ dQ }{dt}$, through the rod in a steady state is given byView Solution
- 3Three 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 junction is......... $^oC$View Solution
- 4The ends of two rods of different materials with their thermal conductivities, radii of cross-sections and lengths all are in the ratio $1:2$ are maintained at the same temperature difference. If the rate of flow of heat in the larger rod is $4\;cal/\sec $, that in the shorter rod in $cal/\sec $ will beView Solution
- 5View SolutionIn which case the thermal conductivity increases from left to right
- 6$Assertion :$ A brass tumbler feels much colder than a wooden tray on a chilly day.View Solution
$Reason :$ The thermal conductivity of brass is more than the thermal conductivity of wood.
- 7Spheres $P$ and $Q$ are uniformly constructed from the same material which is a good conductor of heat and the radius of $Q$ is thrice the radius of $P$. The rate of fall of temperature of $P$ is $x$ times that of $Q$ when both are at the same surface temperature. The value of $x$ is :View Solution
- 8The temperature of a body falls from ${50^o}C$to ${40^o}C$ in $10$ minutes. If the temperature of the surroundings is ${20^o}C$ Then temperature of the body after another $10$ minutes will be ........ $^oC$View Solution
- 9Five identical rods are joined as shown in figure. Point $A$ and $C$ are maintained at temperature $120^o C$ and $20^o C$ respectively. The temperature of junction $B$ will be....... $^oC$View Solution
- 10A wall consists of alternating blocks of length $d$ and coefficient of thermal conductivity $K_{1}$ and $K_{2}$ respectively as shown in figure. The cross sectional area of the blocks are the same. The equivalent coefficient of thermal conductivity of the wall between left and right isView Solution
