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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 F-number, 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 Hard-boiled 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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This note was uploaded on 11/08/2011 for the course PHYS 0000 taught by Professor Na during the Spring '11 term at Rensselaer Polytechnic Institute.
- Spring '11