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Unformatted text preview: Theory Question 3 Page 1 of 8 Theory Question 3 This question consists of five independent parts. Each of them asks for an estimate of an order of magnitude only, not for a precise answer. Enter all your answers into the Answer Script . Digital Camera Consider a digital camera with a square CCD chip with linear dimension L = 35 mm having N p = 5 Mpix (1 Mpix = 10 6 pixels). The lens of this camera has a focal length of = 38 mm. The well known sequence of numbers (2, 2.8, 4, 5.6, 8, 11, 16, 22) that appear on the lens refer to the so called Fnumber, which is denoted by and defined as the ratio of the focal length and the diameter D of the aperture of the lens, . f # F D f F / # = 3.1 (1.0) Find the best possible spatial resolution min x Δ , at the chip, of the camera as limited by the lens. Express your result in terms of the wavelength λ and the F number and give the numerical value for # F λ = 500 nm. 3.2 (0.5) Find the necessary number N of Mpix that the CCD chip should possess in order to match this optimal resolution. 3.3 (0.5) Sometimes, photographers try to use a camera at the smallest practical aperture. Suppose that we now have a camera of = 16 Mpix, with the chip size and focal length as given above. Which value is to be chosen for such that the image quality is not limited by the optics? N # F 3.4 (0.5) Knowing that the human eye has an approximate angular resolution of φ = 2 arcmin and that a typical photo printer will print a minimum of 300 dpi (dots per inch), at what minimal distance should you hold the printed page from your eyes so that you do not see the individual dots? z Data 1 inch = 25.4 mm 1 arcmin = 2.91 × 10 − 4 rad Theory Question 3 Page 2 of 8 Hardboiled egg An egg, taken directly from the fridge at temperature = 4 ° C, is dropped into a pot with water that is kept boiling at temperature . T 1 T 3.5 (0.5) How large is the amount of energy U that is needed to get the egg coagulated?...
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 Spring '11
 NA
 Thermodynamics, Heat, Blood vessel, Digital camera

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