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

Determine the speed of ball, Tiger Woods can hit a golf ball with 55 N of f...

Tiger Woods can hit a golf ball with 55 N of force. How hard does the ball hit back on the club? (a) more than 55 N of force, (b) less than 55 N of force, (c) exactly 55 N of force

Determine state of calcium atom, Ca has atomic no. 20 and atomic weight 40....

Ca has atomic no. 20 and atomic weight 40. Which of the following statements is not correct about Ca atom: (1)The number of electrons is same as the number of neutrons   (2)

Estimate the temperature of vapour pressure, The vapour pressure of a subst...

The vapour pressure of a substance at  20.0 o C is 38.1  kPa and its enthalpy of vaporisation is 49.6  kJ mol -1 . Estimate the temperature at which its vapour pressure is 80.0 k

Discuss about the single-mode fibre in short, Discuss about the Single-mode...

Discuss about the Single-mode fibre in short. Single-mode fibre: A single-mode fibre consists of a narrow core (8 to 10µm) and refractive index in between the core and cladd

Thermoelectric power:, The rate of modification of thermo emf with the chan...

The rate of modification of thermo emf with the change in the temperature of the hot junction is known as thermoelectric power.

Find weight of picture frame, a picture frame is hanging by two verticle st...

a picture frame is hanging by two verticle strings the tention in the string are 3.8N and 4.4N find the weight of the picture frame

The broken pencil-ray optics, The Broken Pencil-Ray Optics A general cl...

The Broken Pencil-Ray Optics A general classroom demonstration includes placing a pencil (or similar object) within an upright position within a round glass of water. The penci

Define the intensity of the laser in short, Define the Intensity of the las...

Define the Intensity of the laser in short. Intensity: a. Lasers are intense and bright light sources. It is due to coherence and directionality. b. The  intensity  is  e

What are the applications of laser transitions, What are the applications o...

What are the applications of laser transitions? Applications of laser transitions: a. High coherence of light is helpful for measuring length precisely by interferometry or

Two simple harmonic motions have different amplitudes, When the two simple ...

When the two simple harmonic motions have dissimilar amplitudes and also vary in phase but they have the similar periodic time : The resultant curve may be obtained graphically

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