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

Component addition of vector, Component Addition of vector We learned i...

Component Addition of vector We learned in which vectors oriented at right angles to one another could be added together by using the Pythagorean Theorem. For example, two disp

How long does ball is taken when it throws vertically, A boy throws a ball ...

A boy throws a ball vertically upward with a velocity of 6 meters per second. How long does it take the ball to return to the boy's hand? Ans: A boy throws a ball vertically

Measurement of the thickness of a thin transparent mica slit, Q.   Describe...

Q.   Describe the method of measurement of the thickness of a thin transparent mica slit using Fresnel's Bi-prism. Give necessary theory. Draw suitable diagram. Measurement of

Explain radio isotopes, What are radiation hazards? Mention four safety mea...

What are radiation hazards? Mention four safety measures which should be taken against radioactive radiation.  OR Explain radio isotopes? Write their any four uses. Descri

Give three applications of photoelectric cells, Q. Give three applications ...

Q. Give three applications of photoelectric cells. (i) Photoelectric cells are utilized for reproducing sound in cinematography. (ii) They are utilized for controlling the

Homework help, Describe an actual situation that would give rise to the fre...

Describe an actual situation that would give rise to the free body diagram

Easier to pull a lawn roller than to push it, Explain why easier to pull a ...

Explain why easier to pull a lawn roller than to push it? Explaination :  In Pulling, effective weight of lawn mover= mg-fsinx In pushing, effective weight = mg+

Evaluate the speed will the string break, Evaluate the speed will the strin...

Evaluate the speed will the string break A certain string just breaks when it is under400N of tension. A boy uses this string to whirl a 10-kgstone in a horizontal circle of rad

Explain electric potential inside hollow conducting shell, Five coulombs of...

Five coulombs of charge are placed on a thin-walled conducting shell. Once the charge has come to rest, the electric potential inside the hollow conducting shell is found to be:

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