Question 90 - In the calculation of the growth of bacteria, absorbance, A in spectrophotometry is used. According to Beer-Lambert Law, A = e x l x c where A is the absorbance of the solution (no unit), l is the distance of light travels through the solution (in cm), e is the molar absorptivity or the molar extinction coefficient [ in L / (mol.cm) ]. For a particular solute and fixed path length : As / Ao = Cs / Co where Ao is the observed signal for a known concentration Co, and As is the observed signal for a sample concentration Cs. (a) For a cell concentration of 560 cells / mL, a spectrophotometre gives an absorbance reading of 1.0. A mixture of concentration 3600000 cells / mL can be diluted in several operations, with each operation having a dilution of 1:20. How many dilutions should be made so that the concentration of this mixture can be calculated within a range of A = 0.0 to 1.0. (b) In another experiment, a sample tube of 1 cm in width is used. Let A = 0.06 and e = 0.0012 ml / (cell.cm). Find the cell concentration of the sample.

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What kind of concerns is associated with temperature pinch points in condensers?

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How can we identify a poisoned food if we are not able to sense it?? . .,(naturally by colour ,smell etc. . .)

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What factors should be compared when evaluating cooling tower bids?

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How fouling effected the heat transfer rate?

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what is mean by refinery

3 Answers   Reliance,

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Explain the common failure mechanism for above ground atmospheric storage tanks?

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CHEMICAL FLUID MECHANIC - EXAMPLE 3.2 : The terminal velocity of a falling object, v is given by v = sqrt [ 4g (R - r) D / (3Cr) ] where sqrt is the square root of, g = 9.81, D = 0.000208, R = 1800, r = 994.6, m = 0.000893. The Reynold number, L is given by L = rD (v) / m. The C for various conditions are : C = 24 / L for L < 0.1; C = 24 (1 + 0.14 L^0.7) / L for 0.1 <= L <= 1000; C = 0.44 for 1000 < L <= 350000; C = 0.19 - 80000 / L for 350000 < L. Find the value of v for the situation above by trial and error, ^ is power, <= is less than or equal to.

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how much time will take 20000 liter water to cool from 80-30 0C ? Assume all parameters constant

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I would like to know how to size a partial combustion reactor processing methane and oxygen, as a function of the flowrate and of the pressure.

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which is the major cement producing state in western India ?

2 Answers   BNPM,

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How can you separate hydrogen peroxide into hydrogen and oxygen?

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