Spectrochemical Analysis
WHAT IS ELECTROMAGNETIC RADIATION?
It is a form of energy that has both properties of wave and particle. Having this, it generally does not require a supporting medium as to that of the sound, thus passing readily in a vacuum.
Electromagnetic radiation is represented as electric and magnetic field that undergo in phase
Properties:
Period (p) the time required for one cycle to pass a fixed point in space.
Frequency (V) the number of cycles which pass a fixed point in space per second. =1/p
Amplitude (A) The maximum length of the electric vector in the wave (Maximum height of a wave).
Wavelength (λ) The distance between two identical adjacent points in a wave (usually maxima or minima).
Wavenumber (1/λ) The number of waves per cm in units of cm-1.
Velocity of propagation = vi = V . λi
Speed of light = Frequency x Wavelength
The speed in vacuum for electromagnetic waves is constant (2.99792×10^8 m/s) which is 0.03% more of that of the speed in the air. For either of the medium to be used by the constant, they used 3.00×10^8 m/s instead.
Planck’s Equation: E = hV ;
Where h = Planck’s constant
= 6.6 x 10-27 erg.sec = 6.6 x 10-34 joule.sec
ELECTROMAGNETIC SPECTRUM
The Higher the Frequency the Shorter the Wavelength
The Longer the Wavelength, Lower the Frequency.
INTERACTION OF RADIATION AND MATTER
SPECTROSCOPY AND THE DISCOVERY OF ELEMENTS
Each natural element has a characteristic light spectrum that helps identify it in samples of unknown substances. Spectroscopy is the practice of examining spectra and comparing them to those of known elements. Using spectroscopy methods, scientists can identify pure substances or compounds and the elements in them. Because it is based on light, spectroscopy works equally well whether the sample is on your desktop or many light-years distant. (seattle pi)
WHY IS THE RED SOLUTION RED?
Objects appear different colours because they absorb some colours (wavelengths) and reflected or transmit other colours. The colours we see are the wavelengths that are reflected or transmitted.
For example, a red shirt looks red because the dye molecules in the fabric have absorbed the wavelengths of light from the violet/blue end of the spectrum. Red light is the only light that is reflected from the shirt. If only blue light is shone onto a red shirt, the shirt would appear black, because the blue would be absorbed and there would be no red light to be reflected.
White objects appear white because they reflect all colours. Black objects absorb all colours so no light is reflected. (sciencelearn.org)
Emission of Electromagnetic Radiation
An electromagnetic field is an area made up of two types of fields, an electrical field and a magnetic field. Both fields are produced when electricity (specifically alternating current) passes through a wire. So, when you plug your iPhone into the wall outlet for charging, a rush of electricity charges the battery creating an electrical field. Continuous movement of electrons generates a magnetic field. You combine the two fields, and you end up with an electromagnetic field or EMF for short.
An electrical field is weakened by physical barriers like concrete walls. On the other hand, a magnetic field can traverse walls, our bodies and other materials. It’s because of this fact that authorities focus more on magnetic fields in relation to our health. EMFs can influence your body and impair your health and that of your children as well. Biological effects are measurable responses to a change in the environment and are not necessarily bad, but if these changes cause long term stress to your system, they may be hazardous to your health and become an adverse effect.
Most of the effects of EMFs are biological effects. Microscopically speaking, EMFs can have effects on our bodies at the cellular level. They heat up our cells and tissues and the amount our tissues are heated is roughly equivalent to the level of EMF we’re exposed to. (energicx)
vid: http://gsp.humboldt.edu/OLM/Courses/GSP_216_Online/lesson1-2/emr.html
Fundamentals of Analytical Chemistry 