Question

1.Describe in detail the effect caused by radiation on a) IR, b) UV and c) microwave radiation?

2.The Planck equation, DE = hu, allows to calculate the energy of any type of radiation, however in the IR for convenience and easy handling of the energy value it is preferred to use the inverse of the l in cm-1, which known as the wave number. What is the expression for the Planck equation as a function of the wave number? Apply it to calculate the energy when l is equal to 3.0 μ. Emphasize the units

3.What causes exposure or proximity in humans: a) to an IR lamp, b) spending an hour under the sun, c) taking a plate with X-rays or obtaining an MRI? Explain in detail and then justify whyWhat causes exposure or proximity in humans: a) to an IR lamp, b) spending an hour under the sun, c) taking a plate with X-rays or obtaining an MRI? Explain in detail and then justify why

4.What functional groups show absorptions dependent on the substituents and the degree of symmetry around them?

5.What type of vibration requires more energy to produce, one of stretching or one of bending? (two)

6. How is a (CH3) 2CH- group recognized by IR? Refer to a specific compound that is not an alkane. (4)

7.Which C = O aliphatic group absorbs more to the right of the IR spectrum? Show an example and explain the reason. (3)

8.. What functional groups show characteristic absorptions in the region of traces of the IR spectrum? Provide one molecule for each case

Answer 1

1A)

A) infrared radiation

The cause multiple effects such as

-green house effect

The earth’s surface atmosphere absorb radiation from the sun’s rays and then re-emit it as IR rays back into the atmosphere.when the air above the earth’s surface has a high concentration of oxides of sulfur and N2, water vapour, and chemicals such as CFCs.the infrared radiation becomes trapped on the earth.The trapped radiation causes increased temperatures and changes in climatic conditions

-damage to eye and skin

B) UV radiation

-activation of vit D

Picture source Stanford.Edu.in

-photosynthesis in plants

-Disinfection and sterilization process

The uv raDiatIon cause inhospitable conditions to bacteria and other microorganisms

2A)

Plank's equation as a function of wave number

the radiation emitted by the black body (energy)

1 micron = cm

Wave number in Planck equation is in cm-1

So the equation contains v instead of

3A)

Let's check all the cases

MRI doesn't actually exposes to any radiation, the work on the principle of magnetic resonance, so there is no doubt of exposure.

UV rays can cause serious exposure UV contains 2 types of rays uvA and uvB which when prolonged exposed are very harmful but depend on many factors such as amount of melononie present, age, diet etc

IR lamps exposures are very rare they are now used as Muscle Massagee for cramps and other muscle ailments

Out of all the 3 UV exposure is most dangerous

5A)

Stretching vibrations requires more energy than bending vibrations