Help in aprobelem

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ahmedfawzika
Posts: 1
Joined: Thu Jul 29, 2010 5:11 am

Help in aprobelem

Post by ahmedfawzika » Thu Jul 29, 2010 5:22 am

hi
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



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