What percentage of incident quanta are transmitted in the example?

• A. 80%
• B. 20%
• C. 50%
• D. 60%

Answer: (A)

Transmission is the fraction of incident quanta that pass through a medium. When the data show that 80% of the incoming quanta make it to the other side, that number directly represents the transmitted portion. Put simply, if 100 photons arrive, 80 emerge on the far side and the remaining 20 are not transmitted, having been absorbed or reflected. The percentage is found by dividing the transmitted amount by the incident amount and multiplying by 100, so 0.80 × 100% equals 80%. The other options would only be correct if the data indicated that fewer quanta were making it through, which isn’t the case here.