Student measured the absorbance of substance x in aqueous solution depending on concentration. he used 0.5 cm cuvette for his measurements; concentration was expressed in moles/l and plotted on x-axis, while absorbance was on y-axis. his data were best fitted by the straight line with equation y = 2120x + 0.0112. the extinction coefficient for substance x in aqueous solution is:

The extinction coefficient is 4240 M⁻¹cm⁻¹

Explanation:

The Beer-Lambert law for the absorbance of a monochromatic light by a molecule is given by the following mathematical expression:

----------------------(1)

Here, E is the extinction coefficient, b is the length of light pathway through the solution and C is the concentration in mol/L. This is a linear equation and fits well with its formula  

y = mx + C-------------------(2)

Here, m is the slope and C is the y intercept. y and x are the two variables. Comparing  equation 1 and 2, Absorbance (A) and molar concentration (C) are the two variables, while the product of extinction coefficient (E) and path length (b) makes the slope of the line. The y-intercept in the given equation is due to the solvent interference.

From this information, we can determine the extinction coefficient by the slope of the line with the following formula.

the ozone layer acts as a filter for the shorter wavelength and highly hazardous ultraviolet radiation (uvr) from the sun, protecting life on earth from its potentially harmful effects. when the sky is clear, there is an inverse relationship between stratospheric ozone and solar uvr measured at the earth's surface.

on passing the small ampere of electric current through the tube made of ar and hg of cfl generates uv rays which excites the fluorescent and thus emits the high radiation by consumption of just 5- 12 w in comparison to incandescent light which requires more power such as around 40 - 55 w to lighten.

moreover the life span of fluorescent or cfl is around 8000 h whereas the life span of incandescent is around 1200 h

hence, the building installed with incandescent lights bears more electricity bill.