The best ideal black body is
Lamp of charcoal heated to high temperature
Metal coated with a black dye
Glass surface coated with coalter
Hollow enclosure blackened inside and having a small hole
Additional Questions
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The rate of cooling of a body is 0.5°C/minute, when the body is 50°C above the surrounding. What is the rate of cooling if the body is 30°C above the surrounding? |
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Coefficient of transmission and coefficient of reflection for a given body are 0.22 and 0.74 respectively. Then, at a given temperature, the coefficient of emission for the body is |
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Wien’s constant units is |
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A body radiates heat at the rate of 4 cal/m2/s, when its temperature is 227°C. what is the heat radiated by the same body when its temperature is 727°C? |
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The earth receives at its surface radiation from the sun at the rate of 1400 W/$m^{2}$. The distance of the centre of the sun from the surface of the earth is 1.5 × $10^{11}$ m and the radius of the sun is 7.0 × $10^{8}$ m. Treating sun as a black body, it follows from the above data that its surface temperature is, |
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Two thermometers A and B exposed to sunlight. The value of A is painted black but that of B is not painted. The correct statement regarding this case is |
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Two spheres made of same material have radii in the ratio 2: 1. if both the spheres are at same temperature, then what is the ratio of heat radiation energy emitted per second by them? |
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The temperature of a black body is gradually increased. The colour of the body will change from |
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A black body at hot temperature at 227°C radiates heat at a rate of 5 cal/$cm^{2}$s. at a temperature of 727°C the rate of heat radiated per unit area will be |
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Radiation emitted by a surface is directly proportional to |
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