Mechanical Properties of Fluids

Question

The temperature of surface of the sun is approximately 6000K. Is it possible to produce a temperature of 7000K by focussing the rays using a big lens?

Answer

This case is not possible because it  is violating the Clausius statement of second law of thermodynamic.
Clausius stated that we cannot transfer heat from a body of low-temperature (6000K) to a body of high-temperature (8000 K), merely by using a lens. 

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