i have a problem and i need a solution to it,
What is the smallest spot you can focus from a sun ideal parallel beam of light with a lens of D= 10 cm and F focal length= 100 cm knowing that power density of the sun is 1 KW/ M2?
and if the focused spot is 1mm in diameter, what is the sun power density in the spot?
i hope that some one can help me....
thanks a lot