Question

Which spectroscopy is more sensitive: fluorescence or absorption? Why? (2) Between fluorescence and phosphorescence: which one has a higher intensity? Which one lasts longer?

Answer 1

Ans- In spectrophotometer we generally used to measure the absorbance of a molecule with a particular or defined wavelength .in spectrophotometer we used to measure fluorescence of a particular compound .Fluorescence occurs when a molecule absorbs energy in the form of light and then immediately releases this energy again in the form of light.
Excitation wavelength - characteristic wavelength that molecule absorbs
Emission wavelength - characteristic wavelength that molecule emits .
the basic aim of both the methods are same ie to detect the amount or Presence of a predefined compound .
the basic difference of both the methods are stated below
emitted light read at right angles to the exciting light, minimizing background signal
fluorescent methods have a greater range of linearity
Because of these differences, the sensitivity of fluorescence is approximately 1000 times greater than absorption spectrophotometric methods .