The giant hornet Vespa mandarinia japonica preys on Japanese bees. However, if one of the hornets attempts to invade a beehive, several hundred of the bees quickly form a compact ball around the hornet to stop it. They don't sting, bite, crush, or suffocate it. Rather they over heat by quickly raising their body temperatures from the normal 35oC to 47oC or 48oC, which is lethal to the hornet but not to the bees (Figure). Assume the following: 500 bees form a ball of radius R = 2.0 cm for a time t = 20 min, the primary loss of energy by the ball is by thermal radiation, the ball's surface has emissivity ? = 0.80 and the ball has a uniform temperature. On average, how much additional energy must each bee produce during the 20 min to maintain 47oC?

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3. C