Absorbance spectrophotometer , Physics

Assignment Help:

Absorbance spectrophotometer:

A schematic diagram of a simple instrument that is used to measure the absorption of visible light is shown in Figure below.

1116_absorbance spectrophotometer.png

When studying a compound in solution by spectrophotometry, you put it in a sample holder called a cuvette and place it in the spectrophotometer.  Light of a particular wavelength passes through the solution inside the cuvette and the amount of light transmitted (passed through the solution-Transmittance) or absorbed (Absorbance) by the solution is measured by a light meter. While a spectrophotometer can display measurements as either transmittance or absorbance, in biological applications we are usually interested in the absorbance of a given sample.

Because other compounds in a solution (or the solvent itself) may absorb the same wavelengths as the compound being analyzed, we compare the absorbance of our test solution to a reference blank.  Ideally, the reference blank should contain everything found in the sample solution except the substance you are trying to analyze or measure. For instance, in today's lab exercise you will be measuring the absorbance of a dye, bromphenol blue that was dissolved in water. The reference blank in this case would be water alone.

The amount of light transmitted through a solution is referred to as transmittance (T). The transmittance is defined as the ratio of the light energy transmitted through the sample (I) to the energy transmitted through the reference blank (I0). Since the compound being tested is not present in the reference blank, the transmittance of the reference blank is defined as 100%T.


Related Discussions:- Absorbance spectrophotometer

Gold, Gold:                          Atomic number ...

Gold:                          Atomic number 79 Symbol Au Atomic weight 196.9665 discov

Explain the types of polymorphism, Explain the types of polymorphism In...

Explain the types of polymorphism In terms of  thermodynamics, there are two kinds of polymorphism. For a monotropic system, a plot of the free energy of the various polymorphs

The magnetic circuit, THE MAGNETIC CIRCUIT In an electric circuit, a cu...

THE MAGNETIC CIRCUIT In an electric circuit, a current is established due to the existence of an electromotive force. In the same way, in a magnetic circuit, a flux is establis

Time dilation (relativity of time), Time dilation (relativity of time) is ...

Time dilation (relativity of time) is the proper time interval is dilated when it is measured by an observer with reference to whom it has uniform velocity v  This is known as

Second, Second; s: The basic SI unit of time, explained as the period ...

Second; s: The basic SI unit of time, explained as the period of time equal to the duration of 9 192 631 770 periods of the radiation equivalent to the transition among two hy

Discharging of solar cell, Discharging: The cell is connected across some ...

Discharging: The cell is connected across some load during discharging. As the direction of current by the cell is reversed during discharging the negative ions go in the directio

Determine the distance between crests of the wave, A Surfer sits on his boa...

A Surfer sits on his board waiting as waves go by to catch a ride back to shore. Assuming the waves can be modelled as a sine wave given by h (x,t) = 1.75 sin (0.03 Πx - 0.15 Πt) [

Motion in one dimension, #question.A tortoise can run with a speed of 0.12 ...

#question.A tortoise can run with a speed of 0.12 m/s, and a hare can run 20 times as fast. In a race, they both start at the same time, but the hare stops to rest for 4.0 minutes.

Electric current, A battery of emf 2v and internal resistance 0.1 ohm is be...

A battery of emf 2v and internal resistance 0.1 ohm is being charged with a current of 5A. In what direction will the current will flow inside the battery? Ans) In charging cond

Hubbles law, Hubble's law (E.P. Hubble; 1925): A relationship discover...

Hubble's law (E.P. Hubble; 1925): A relationship discovered among distance & radial velocity. Further away a galaxy is away from is, the quicker it is receding away from us. T

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd