Question

1. calculate the medullary index of a hair whose diameter is 110 microns wide and whose medulla measures 58 microns. is this a human or animal hair? obj. 3.3 and 3.6

Explanation:

Step1: Recall the formula for medullary index

The medullary index is calculated as $\frac{\text{Medulla width}}{\text{Hair diameter}}$.

Step2: Substitute the given values into the formula

Given that the medulla width is $58$ microns and the hair diameter is $110$ microns. So, the medullary index $=\frac{58}{110}\approx0.53$.

Step3: Determine if it is human or animal hair

For human hair, the medullary index is generally $\leq0.33$. For animal hair, the medullary index is $> 0.33$. Since $0.53>0.33$, this is an animal hair.

Answer:

The medullary index is approximately $0.53$ and this is an animal hair.