Question

Find the optical density and transmittance of 0.04%lactose solution if 1/8of intial light intensity is absorbed in it

Answer 1

By definition, the transmittance is the fraction of incident electromagnetic power (intensity) that is transmitted through a sample. Thus:

$$T = \dfrac{I_t}{I_0}$$

where $I_t$ is tramsmited intensity, and $I_0$ is incident. If 1/8 of intial light intensity is absorbed in the solution, then

$$T = 1/8 = 0.125$$

By definition, the optical density is

$$D = -\log_{10}T = -\log_{10}(1/8) \approx 0.903$$

Answer. D = 0.903, T = 0.125.