P18_087 - 87. The source being isotropic means Asphere =...

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87. The source being isotropic means A sphere =4 πr 2 is used in the intensity defnition I = P/A ,wh i ch Further implies I 2 I 1 = P/ 4 πr 2 2 P/ 4 πr 2 1 = µ r 1 r 2 2 . (a) With I 1 =9 . 60 × 10 4 W/m 2 , r 1 =6 . 10 m, and r 2 =30 . 0 m, we fnd I 2 =0 . 960(6 . 10 / 30 . 0) 2 = 3 . 97 × 10 5 W/m 2 . (b) Using Eq. 18-27 with I 1 =9 . 60 × 10 4 W/m
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This note was uploaded on 11/12/2011 for the course PHYS 2001 taught by Professor Sprunger during the Fall '08 term at LSU.

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