This online calculator helps to determine the intensity of a monochromatic light beam after passing through an absorbing medium. According to the law, the intensity of the monochromatic light decreases exponentially with the concentration and thickness of the medium. The formula is given by,

I = $I_{0}e^{-\mu x}$

where, **I**= intensity after absorption,**$I_{0}$**= initial intensity,**$\mu$**= absorption coefficient,**x**= thickness of the medium.**Step 1 :**From the given question, note down the values of the parameter.

**Step 2 :**Substitute these values in the given formula and find out the required value,

I = $I_{0}e^{-\mu x}$.

Let us discuss the problems related to Beer Lambert Law.

### Solved Examples

**Question 1:**Calculate the intensity of a monochromatic light which is passed through a medium of thickness 0.1m. The initial intensity is given as 25mW and the absorption coefficient is 0.3m

^{-1}.

**Solution:**

Given that,

$I_{0}$ = 25mW,

$\mu$ = 0.3m

^{-1},

x = 0.1m.

Intensity of a monochromatic light is,

I = $I_{0}e^{-\mu x}$

I = 25$\times e^{-0.3\times0.1}$

I = 25$\times$0.970445 = 24.26

**Question 2:**Calculate the intensity of a monochromatic light which is passed through a medium of thickness 0.05m. The initial intensity is given as 15mW and the absorption coefficient is 0.6m

^{-1}.

**Solution:**

Given that,

$I_{0}$ = 15mW,

$\mu$ = 0.6m

^{-1},

x = 0.05m.

Intensity of a monochromatic light is,

I = $I_{0}e^{-\mu x}$

I = 15$\times e^{-0.6\times0.05}$

I = 15$\times$0.970445 = 14.556