Pre-Assignment

1. If the intensities of the sample and reference beam are both the same, what is the value of absorbance?
2. What is the % transmission for an absorbance of 1?
3. What is the unit of the absorbance?
4. 'HOMO-LUMO electronic transitions are properties of the groups of atoms.' Is the statement true or false?
5. What kinds of electronic transitions are observed in carbonyl compounds?
6. How are the absorbance and transmittance related at the spectral peak position?

Post-Assignmnt

1. What kind of cuvettes (glass or quartz) will you use for a wavelength scan spanning the UV-visible range?
2. What do you expect if you run the wavelength scan by mistakenly placing the sample in the reference holder and the sample blank or reference in the sample holder?
3. It is necessary not to touch the cuvette on sides that come across the light path and wipe out gently all the sides with lint free paper. Why?
4. What does an absorption spectrum of a sample tell about the colour of the sample?
5. Though caffeine absorbs light, yet it is colourless. Why?
6. How do the samples look like in following two cases: when absorbance values of the samples are (i) close to zero and (ii) very high in the entire visible range?
7. Which compound of the two studied here absorbs light of higher energy per photon?
8. Which colors of light do caffeine and potassium dichromate absorb?