Question

If the reflectance of a dyed fabric at \( \lambda_{max} \) is 10%, then the colour strength value (K/S) of the dyed fabric (correct up to 2 decimal places) is ________________.

Hint:

The K/S value is used to indicate the colour strength, which is a measure of the intensity of the colour in a fabric.

Answer 1

Correct Answer: 4

The colour strength value (K/S) is calculated using the formula: \[ K/S = \frac{(1 - R)^2}{2R}, \] where \( R \) is the reflectance. Substituting \( R = 0.10 \) (reflectance of 10%): \[ K/S = \frac{(1 - 0.10)^2}{2 \times 0.10} = \frac{(0.90)^2}{0.20} = \frac{0.81}{0.20} = 4.05. \] Final Answer: \[ \boxed{4.05}. \]