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A black body at $1227^o C$ emits radiations with maximum intensity at a wavelength of $5000\;\mathring A$ . If the temperature of the body is increased by $1000^o C$, the maximum intensity will be observed at ...... $\mathring A$
Energy is being emitted from the surface of a black body at ${127^o}C$ temperature at the rate of $1.0 \times {10^6}J/\sec - {m^2}$. Temperature of the black body at which the rate of energy emission is $16.0 \times {10^6}J/\sec - {m^2}$ will be......... $^oC$
A black body calorimeter filled with hot water cools from $60^o C$ to $50^o C$ in $4 \,\,min$ and $40^o C$ to $30^o C$ in $8 \,\min$. The approximate temperature of surrounding is ........ $^oC$
Parallel rays of light of intensity $I =912 \ Wm ^{-2}$ are incident on a spherical balck body kept in surroundings of temperature $300 \ K$. Take Stefan-Boltzmann constant $\sigma=5.7 \times 10^{-8} Wm ^{-2} K ^{-4}$ and assume that the energy exchange with the surroundings is only through radiation. Th final steady state temperature of the black body is close to:
A small object is placed at the center of a large evacuated hollow spherical container. Assume that the container is maintained at $0 K$. At time $t =0$, the temperature of the object is $200 K$. The temperature of the object becomes $100 K$ at $t = t _1$ and $50 K$ at $t = t _2$. Assume the object and the container to be ideal black bodies. The heat capacity of the object does not depend on temperature. The ratio $\left( t _2 / t _1\right)$ is. . . . .
Two identical objects $A$ and $B$ are at temperatures $T_A$ and $T_B$ respectively. Both objects are placed in a room with perfectly absorbing walls maintained at temperatures T $({T_A} > T > {T_B}).$ The objects A and B attain temperature $T $ eventually which one of the following is correct statement
The 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 be
Energy is being emitted from the surface of a black body at $127\,^oC$ temperature at the rate of $1.0 \times {10^6}\,J/s - {m^2}$. Temperature of the black body at which the rate of energy emission is $16.0 \times {10^6}\,J/s - {m^2}$ will be ......... $^oC$
If the temperature of the sun were to be increased from $T$ to $2T$ and its radius from $R$ to $2R$ , then the ratio of the radiant energy received on the earth to what it was previously will be