Calculate the approximate wave number and frequencies of fundamental absorption peak due to stretching vibration of carbonyl group $C=O.$ Atomic mass of $C$ and $O$ are $12$ and $16a.$

How many fundamental vibrational modes and IR absorption bands will the following molecules have? Sketch the IR active and inactive vibrations for each molecules.

a$.C{H}_4,$

b$.C{H}_{3}Cl$

What is an Interferometer and what is its function?

Why $C{O}_2$ has only one strong absorption band?

Which one of the following gives stronger absorption band? Why?

a$.>C=O,$

b$.>C=C$

Describe the mechanism of the following detectors:

a$)$ QWIP,

b$)$ Thermoelectric,

c$)$ Pyroelectric