Continuous absorption spectrum - why this happens?

In summary, when a pure green or red glass plate is placed in the path of light, it appears to only absorb the opposite color. This is due to the way our eyes perceive colors, with different cones sensitive to different wavelengths of light. Therefore, the missing color from the incident light is perceived as its complementary color by our brains. This phenomenon is important to consider in spectroscopy.
  • #1
logearav
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Continuous absorption spectrum -- why this happens?

Homework Statement



A pure green glass plate placed in the path of light, absorbs everything everything except green, similarly red glass plate absorbs everything except red.

Homework Equations


May i know the reason for this? Thanks in advance revered members



The Attempt at a Solution

 
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  • #2


It is not true.
Seeing through, a glass plate if it absorbs red, appears green too. The complementary colour of green is red. If red is removed from white light we see green.

ehild
 
  • #3


My textbook on Spectroscopy mentions like this, but reasons are not given
 
  • #4


Your eyes work this way. The cones of your eyes see the colours. See: http://www.yorku.ca/eye/specsens.htm. Each kind of them are sensitive to a band of wavelength: one to red light, the other to green, the third to blue. If the incident light is red it activates the red cones and they send a signal to the brain: you recognise red color. If the red is missing from the incident light, the green and blue cones activate and you recognize it as some kind of green.
If the green is missing the remaining light activates the blue and red cones, and your brain recognizes it as some kind of red.

ehild
 
  • #5


Thanks for the reply Mr. ehid. But i am raising this question in spectroscopy perspective
 

Related to Continuous absorption spectrum - why this happens?

1. Why does continuous absorption spectrum occur?

The continuous absorption spectrum occurs because molecules have the ability to absorb light at different wavelengths. When light passes through a molecule, the electrons in the molecule can be excited to a higher energy state. The amount of energy required to do this depends on the molecule's structure and composition, resulting in different absorption wavelengths.

2. How is the continuous absorption spectrum different from other types of absorption spectra?

The continuous absorption spectrum is different from other types of absorption spectra, such as line and band spectra, because it shows a continuous range of absorbed wavelengths. Line spectra, on the other hand, show only specific wavelengths being absorbed, while band spectra show a range of wavelengths being absorbed due to the molecular structure of the molecule.

3. What factors affect the continuous absorption spectrum?

The continuous absorption spectrum can be affected by several factors, including the composition and structure of the molecule, the concentration of the molecules, and the physical state of the molecule (solid, liquid, or gas). Temperature and pressure can also affect the continuous absorption spectrum.

4. How is the continuous absorption spectrum measured?

The continuous absorption spectrum is measured using a spectrophotometer, a device that measures the amount of light absorbed by a sample at different wavelengths. The sample is placed in a cuvette and a beam of light is passed through it. The spectrophotometer measures the intensity of the light before and after it passes through the sample, and the difference in intensity is used to determine the amount of light absorbed.

5. What are some practical applications of continuous absorption spectrum?

The continuous absorption spectrum has many practical applications, including in chemistry, biology, and environmental science. It is used to identify and quantify the presence of different molecules in a sample, as well as to study their structure and composition. It is also used in industries such as pharmaceuticals, food and beverage, and environmental monitoring to ensure product quality and safety.

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