Question

When a sample is irradiated with 1000 photons of a certain wavelength of light, 500 photons are detected by UV detector. What are the transmittance (T) and absorbance (i.e. A)? Include your calculation.

Answer 1

Transmittance = I_o / I

[ where , i_o represents intensity of light that goes through (or passes from ) the sample ,and I is intensity of light which enters through the sample ]

& intensity of light = k n .........[ where n = number of photons ; k is a constant ]

   I_o = k n₁ and I = k n₂

Given n₁ = 500 ; & n₂ = 1000

Transmittance = k n₁  / k n₂  

........................... = n₁ / n₂  

............................ = 500 /1000

............................ = 1 /2

expressed as ---- = 50 %

Further , Absorbance = log [ I / I_o ]

...........................or,.... = log [ n₂ / n₁ ]

_{.............................................. =}   log (1000 / 500)

.................................. = 0.3010