1028_Physics ProblemsTechnical Physics

1028_Physics ProblemsTechnical Physics - 369 Chapter 36...

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Chapter 36 369 P36.56 Let I 0 represent the intensity of the light from the nebula and θ 0 its angular diameter. With the first telescope, the image diameter h on the film is given by o o h f =− as ′=− h o 2000 mm bg . The light power captured by the telescope aperture is P 10 2 200 4 == L N M M O Q P P IA I π mm af , and the light energy focused on the film during the exposure is Et I 11 2 200 4 150 L N M M O Q P P mm min a f .. Likewise, the light power captured by the aperture of the second telescope is 20 2 60 0 4 L N M M O Q P P I . mm a f and the light energy is EI t 2 2 60 0 4 = L N M M O Q P P . Therefore, to have the same light energy per unit area, it is necessary that It I o o 0 2 2 2 0 2 2 60 0 4 900 4 200 4 1 50 2000 4 πθ mm mm mm min mm a f = . The required exposure time with the second telescope is t 2 22 2 2 200 900 60 0 2 000 338 mm mm mm mm min min a f a f . . Additional Problems P36.57 Only a diverging lens gives an upright diminished image. The image is virtual and
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This note was uploaded on 12/14/2011 for the course PHY 203 taught by Professor Staff during the Fall '11 term at Indiana State University .

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