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Beer Lambert Law Calculator
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Beer Lambert law named after August Beer tells that about the absorption of a monochromatic light by a solute using the spectrometer. The intensity of a monochromatic light entering an absorbing medium decreases exponentially with the thickness as well as the concentration of the absorbing medium.

The intensity of the transmitted light I is a function of the thickness x of the absorption medium given as
I = Io $e^{- \mu x}$
Here Io is the intensity of incident light
$\mu$ is absorption coefficient
Beer Lambert law Calculator is a online tool to calculate the intensity of the transmitted light I. You just have to enter the given quantities and enter the unknown quantity as x in the block provided and get your answer instantly.
 

Steps for Beer Lambert Law Calculator

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Step 1 :  

Read the given problem and note down the given quantities



Step 2 :  

Use the formula


I = Io $e^{-\mu x}$


Where I is the intensity of transmitted light


Io is the intensity of incident light,
$\mu$ is absorption coefficient,


x is depth of the absorbing medium


Substitute the values in above formula and get the unknown quantity.



Problems on Beer Lambert Law Calculator

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  1. A monochromatic light having the intensity of 2 mW is passed through the transparent glass of 5 cm thickness. Calculate its final intensity after passing through the medium having absorbtion coefficient of 5 cm-1.


    Step 1 :  

    Given: Initial intensity Io = 2 mW, thickness x = 5 cm, absorbtion coefficient $\mu$ = 5 cm-1



    Step 2 :  

    The final intensity is given by
    I = Io $e^{-\mu x}$
      = 2 mW $\times$ $e^{- 5 \times 5}$
      = 2.778 $\times$ 10-11 mW/m2.



    Answer  :  

    The final intensity I = 2.778 $\times$ 10-11 mW/m2.



  2. A torch light has the intensity of 20 mW passes the glass of 2 cm thickness. If the final intensity is 2 $\times$ 10-7 W/m2.Calculate the absorption coefficient.


    Step 1 :  

    Initial intensity Io = 20 mW, thickness x = 2 cm, Final intensity I = 2 $\times$ 10-7 W/m2



    Step 2 :  

    The final intensity is given by
    I = Io $e^{-\mu x}$


    Hence absorption coefficient is


    $\mu$ = $\frac{1}{x}$ $\frac{ln I}{ln I_o}$


              = $\frac{1}{0.02}$ $\frac{ln 2 \times 10^{-7}}{ln 20}$


              = 18.94 mW/m2



    Answer  :  

    Absorbtion coefficient $\mu$ is 18.94 mW/m2



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