Question

Can anyone tell me some about the concepts of transmittance and absorption.

Answer 1

As the name suggests,

If a light passes through any solution without any absorption, the light is said to have 100% transmittance and zero absorption.

Similarly if the light is completely absorbed in the solution, the light is said to have infinite absorption and 0% transmittance.

Transmittance is defined as ratio of outlet radiation power to inlet radiation power to any solution:

T = P/P₀ , % Transmittance(%T) = 100*P/P₀ or (%T) = 100T

Absorbance is not defined in % terms, it is defined in logarthimic scale

A (Absorbance) = Log₁₀ (P₀/P) = -Log₁₀(P/P₀) = -Log₁₀(T) = -Log₁₀ ((%T)/100) = 2-Log₁₀ (%T)

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