A difference of temperature of 25^∘C is equivalent to a difference of.
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A hot liquid is filled in a container and kept in a room of temperature of 25∘C. The liquid emits heat at the rate of 200 Js^−1 when its temperature is 75∘C. When the temperature of the liquid becomes 40∘C, the rate of heat loss is J s^−1 is
12
Sep
A hot liquid is filled in a container and kept in a room of temperature of 25∘C. The liquid emits heat at the rate of 200 Js^−1 when its temperature is 75∘C. When the temperature of the liquid becomes 40∘C, the rate of heat loss is J s^−1 is A difference of temperature of 25^∘C [...]
Two bodies A and B have emissivities 0.3 and 0.6 respectively have maximum spectral emissive powers at wavelength 4000 Å and 2000 Å respectively. The ratio of their emissive powers at A and B at these temperatures is:
12
Sep
Two bodies A and B have emissivities 0.3 and 0.6 respectively have maximum spectral emissive powers at wavelength 4000 Å and 2000 Å respectively. The ratio of their emissive powers at A and B at these temperatures is: A difference of temperature of 25^∘C is equivalent to a difference of. September 12, 2021 Category: Chapter [...]
Spheres 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 :
12
Sep
Spheres 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 [...]
The wall with a cavity consists of two layers of brick separated by a layer of air. All three layers have the same thickness and the thermal conductivity of the brick is much greater than that of air. The left layer is at a higher temperature than the right layer and steady state condition exists. Which of the following graphs predicts correctly the variation of temperature T with distance d inside the cavity?
12
Sep
The wall with a cavity consists of two layers of brick separated by a layer of air. All three layers have the same thickness and the thermal conductivity of the brick is much greater than that of air. The left layer is at a higher temperature than the right layer and steady state condition exists. [...]
Two bodies P and Q have thermal emissivities of ϵ_(P) and ϵ Q respectively. Surface areas of these bodies are same and the total radiant power is also emitted at the same rate. If temperature of P is T_P kelvin then temperature of Q i.e. T_Q is
11
Sep
Two bodies P and Q have thermal emissivities of ϵ_(P) and ϵ Q respectively. Surface areas of these bodies are same and the total radiant power is also emitted at the same rate. If temperature of P is T_P kelvin then temperature of Q i.e. T_Q is A difference of temperature of 25^∘C is equivalent [...]
The intensity of radiation emitted by the sun has its maximum value at a wavelength of 510 nm and that emitted by the North Star has the maximum value at 350 nm. If these stars behave like black bodies, then the ratio of the surface temperature of the sun and North star is:
11
Sep
The intensity of radiation emitted by the sun has its maximum value at a wavelength of 510 nm and that emitted by the North Star has the maximum value at 350 nm. If these stars behave like black bodies, then the ratio of the surface temperature of the sun and North star is: A difference [...]
The spectral emissive power Eλ for a body at temperature T1 is plotted against the wavelength and area under the curve is found to be A. At a different temperature T2 the area found to be 9A. Then λ2 /λ1 is :
11
Sep
The spectral emissive power Eλ for a body at temperature T1 is plotted against the wavelength and area under the curve is found to be A. At a different temperature T2 the area found to be 9A. Then λ2 /λ1 is : A difference of temperature of 25^∘C is equivalent to a difference of. September [...]
Two rods (one semi-circular and other straight) of same material and of same cross-sectional area are joined as shown in the figure. The point A and B are maintained at different temperature. The ratio of the heat transferred through a cross-section of a semi-circular rod to the heat transferred through a cross section of the straight rod in a given time
11
Sep
Two rods (one semi-circular and other straight) of same material and of same cross-sectional area are joined as shown in the figure. The point A and B are maintained at different temperature. The ratio of the heat transferred through a cross-section of a semi-circular rod to the heat transferred through a cross section of the [...]
2 kg of Ice at – 20° C is mixed with 5 kg of water at 20°C in an insulating vessel having a negligible heat capacity calculate the final mass of water remaining in the container. It is given that the specific heats of water and ice care 1 Kcal/kg per °C and 0.5 Kcal/kg 1°C while the latent heat of fusion of ice is 80 Kcal/kg.
11
Sep
2 kg of Ice at – 20° C is mixed with 5 kg of water at 20°C in an insulating vessel having a negligible heat capacity calculate the final mass of water remaining in the container. It is given that the specific heats of water and ice care 1 Kcal/kg per °C and 0.5 Kcal/kg [...]
A solid substance is at 30^∘C. To this substance heat energy is supplied at a constant rate. Then temperature versus time graph is as shown in the figure. The substance is in liquid state for the portion (of the graph)
11
Sep
A solid substance is at 30^∘C. To this substance heat energy is supplied at a constant rate. Then temperature versus time graph is as shown in the figure. The substance is in liquid state for the portion (of the graph) A difference of temperature of 25^∘C is equivalent to a difference of. September 11, 2021 [...]