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Unformatted text preview: 2 (2) (c) At this 7.20 m distance, a lens is set up with its axis pointing toward the lightbulb. The lens has a circular face with a diameter of 15.0 cm and has a focal length of 35.0 cm. Find the diameter of the bulb. (+ 2pts) (+ 1pt) 1 p + 1 q = 1 f 1 7 . 20 m + 1 q = 1 . 350 m q = 0 . 386 m (3) (+ 1pt) M = h h =q p h 3 . 20 cm =. 386 m 7 . 20 m h = 0 . 164 cm (4) (d) Find the light intensity at the image. (+ 2pts) Lens intercepts power given by: (+ 1pt) P = I bulb A = (6 . 91 103 W/m 2 )( 4 (0 . 150 m 2 ) = 1 . 22 104 W (5) and puts it all onto the image with intensity (+ 1pt) I image = P A = 1 . 22 104 W (0 . 00164 m ) / 4 = 57 . 8 W/m 2 (6) Some possibly useful equations: 1...
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 Spring '08
 Wu
 Work, Light

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