Past exam of the physics B course of the University of Cambridge / 2011 / Paper 1 / Section A / A4

Table of contents
- Solution A4

Solution

For a nonabsorbing interface at normal incidence, the Fresnel equations give the intensity reflectance

R = (\frac{n - 1}{n + 1})^{2} = 0.04.

The two air–glass interfaces each transmit a fraction

1 - R

of their incident power. Omitting all internally reflected paths,

\frac{I _{transmitted}}{I _{incident}} = (1 - 0.04)^{2} = 0.9216, reduction = 7.84% ≃ 8%.

The power-transmission factors, rather than electric-field amplitudes alone, are multiplied. Absorption, coatings and interference are excluded by this approximation.

 Ancestors (13)

 View article source

 Discussion (0)

There are no discussions about this article yet.

 Articles by others on the same topic (0)

There are currently no matching articles.

  See all articles in the same topic Create my own version