Infrared radiation is strongly absorbed by water and by the atmosphere. Although invisible to the eye, infrared radiation can be detected as warmth by the skin.
The absorbance (A) of the solution (at a given wavelength) is defined as equal to the logarithm (base 10) of 1÷T. That is, A = log (1÷T). The absorbance of the solution is directly proportional to the concentration (c) of the absorbing material in solution. That is, A = kc, where “k” is a proportionality constant.
Beer’s law relates the concept of concentration and absorbance. If you increase the original concentration, the absorbance increases and if you dilute the solution(which means you decrease the original concentration), the absorbance will decrease in direct proportion.
UV -B, the frequency range of ultra-violet light that causes sunburn, is absorbed by water but you need a few metres of it to provide adequate protection. Half a metre of water will still let 40 per cent of the UV -B through and the cooling effect of the water makes you less aware of the Sun.
The red, yellow, and green wavelengths of sunlight are absorbed by water molecules in the ocean. When sunlight hits the ocean, some of the light is reflected back directly but most of it penetrates the ocean surface and interacts with the water molecules that it encounters.
Blue penetrates the deepest, which is why deep, clear ocean water and some tropical water appear to be blue most of the time.
Absorbance is a measure of the quantity of light absorbed by a sample. If all light passes through a sample, none was absorbed, so the absorbance would be zero and the transmission would be 100%. On the other hand, if no light passes through a sample, the absorbance is infinite and the percent transmission is zero.
The two main factors that affect absorbance are concentration of the substance and path length. Relation between concentration and absorbance: Absorbance is directly proportional to the concentration of the substance. The higher the concentration, the higher its absorbance. This increases the absorbance.
Negative absorbances have meaning and should not be discarded. A negative absorbance means that the the intensity of light passing through the sample is greater than the intensity of light passing through the reference. If the experiment is performed correctly, a negative absorbance may have an important significance.
The most absorbance occurs when the beam is a different color than the solution.
The absorbance is directly proportional to the concentration (c) of the solution of the sample used in the experiment. The absorbance is directly proportional to the length of the light path (l), which is equal to the width of the cuvette.
The Beer Lambert law, which is also referred to as Beer’s Law, describes the relationship among absorbance (A), the molar solute concentration in M (c), and the length of the path the light takes to get to the sample in centimeters ( l ). Absorbance is directly proportional to concentration and length: A = εcl.
UVC radiation is commonly used inside air ducts to disinfect the air. This is the safest way to employ UVC radiation because direct UVC exposure to human skin or eyes may cause injuries, and installation of UVC within an air duct is less likely to cause exposure to skin and eyes.
The most common form of UV radiation is sunlight, which produces three main types of UV rays: UVA. UVB. UVC.
UVC is the shortest wavelength of the three forms of UV. The shorter the wavelength, the more harmful the UV radiation. So while UVC is the most dangerous because it’s the shortest wavelength, it’s not a risk to the typical person because the sun’s natural UVC emissions don’t penetrate skin.