A copper sphere is suspended in an evacu...

A copper sphere is suspended in an evacuated chamber maintained at `300K`. The sphere is maintained at a constant temperature of `500K` by heating it electrically. A total of `210W` of electric power is needed to do it. When the surface of the copper sphere is completely blackened, `700W` is needed to maintain the same temperature of the sphere. Calculate the emissivity of copper.

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A copper sphere is suspended in an evacuated chamber maintained at 300 k. The sphere is maintained at a constant temperature of 500 K by heating it electrically. A total of 210 W of electric power is needed to do it. When the surface of the copper shphere is completely blackened, 700 W is needed to maintain the same temperature of the sphere. Calculate the emissivity of copper.

A copper sphere is suspended in an evacuated chamber maintained at 300K. The sphere is maitained at a constant temperature of 500K by heating it electrically. A total of 210W is electric power is needed to do it. When the surface of the copper sphere is completely blackned, 700W is needed to maintain the same temperature of the sphere. Calculate the emissivity of copper.

A copper sphere is suspended in an evacuated chamber maintained at 300 K . The sphere is mantained at a constant temperature of 500 K by heating it electrically. A total of 300 W of electric power is needed to do it. When half of the surface of the copper sphere is completely blackened, 600W is needed to maintain the same temperature of the the sphere. Calculate the emissivity of copper.

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