The effectiveness of an antiseptic or antibiotic
The effectiveness of the chosen antibiotic or antiseptic can be measured numerically by using the formula \( \pi {r}^{2}\). Using the diagram below.
Method
- For \( \pi\) use 3.14. This value may vary slightly in a specific question.
- Measure the diameter of the zone of inhibition and divide it by 2 to find the radius.
- Use the equation: \( \pi {r}^{2}\)
Example
In the diagram below, the diameter of the clear zone around antibiotic sample B is 10 mm.
The radius of the clear zone is 5 mm (\( \text{radius} = \frac{diameter} {2}\))
The area of the clear zone = \( \pi {r}^{2}\)
= 3.14 Ă— 5 Ă— 5
= 3.14 Ă— 25
= 78.5 mm2