Question

2. What are the bands of electromagnetic radiation and how are they related to Energy, Frequency, and Wavelength? 3. For each band of electromagnetic radiation, what effect does it have on an atom or molecule?

please answer both questions thank you.

Answer 1

2.   Electromagnetic spectrum is the range of light radiations of multiple frequencies and wavelengths. Only light rays that fall between certain frequency and wavelength is visible to human eyes, rest are not. The ones that are not visible include low frequency waves, radio waves, microwaves, infrared waves, ultraviolet rays, X-rays, gamma rays.

The electromagnetic radiation are broadly classified into the following classes (bands ):

1. Gamma radiation
2. X-ray radiation
3. Ultraviolet radiation
4. Visible light
5. Infrared radiation
6. Microwave radiation
7. Radio waves

we have,
E = hc
    or
E = hu

where:

• c = 3*10⁸ m/s is the speed of light in a vacuum
• h = 6.626×10⁻³⁴ J·s

Electromagnetic waves are typically described by any of the following three physical properties: the frequency v, wavelength λ, or photon energy E. Wavelength is inversely proportional to the wave frequency, gamma rays have very short wavelengths that are fractions of the size of atoms, whereas wavelengths on the opposite end of the spectrum can be as long as the universe. Photon energy is directly proportional to the wave frequency, gamma ray photons have the highest energy (, while radio wave photons have very low energy .

3. How each band affects an atom or molecule :

1. Gamma radiation : High Energy ejection of core electrons in heavy elements, , excitation of atomic nuclei, including dissociation of nucleus.
2. X-ray radiation : Excitation and ejection of core electrons
3. Ultraviolet radiation : Excitation of molecular and atomic valence electrons, including photoelectric effect.
4. Visible light : Excitation of molecular valence electrons
5. Infrared radiation : Molecular vibration (excitation of vibrational energy states, v).
6. Microwave radiation : Molecular rotation ( excitation of vibrational energy states, J).
7. Radio waves : Oscillation of electric potential