## Dr Dan HalmiEdit

**What is Snell's Law?**Edit

Snell's Law is used to find the relationship between the angle of Incidence and Refraction and the indices of refraction of multiple mediums. Snell's Law can be used to find the refraction of a light ray in any situation, no matter what the different mediums(substances the light passes through) are.

$ n_1\sin(\theta_1) = n_2\sin(\theta_2)\ , $

Snells Law() of llama

- n is equal to the absolute index of refraction
- n is also equal to c/v which is speed of light in a vacuum divided by velocity

- $ theta $ is equal to the angle

### Who created Snell's Law? What is it's history?Edit

Snell's law was first discovered by Ibn Sahl in 984. Sahl used it to work out the shapes of Anaclastic Lenses (lenses that focus light with no geometric aberrations). Later on, it was *discovered* again by Thomas Harriot in 1602, but it was not published. In 1621, it was *discovered* another time by **Willebrord Snell**, in a form that was basically written in a similar mathematical format. This work was never published during Snell's life. René Descartes independently derived the law in terms of sines in his 1637 treatise *Discourse on Method*, and used it to solve a range of optical problems. Despite the many people who have worked on Snell's Law over the years, only Willebrord Snell is mentioned in its name.

Thomas Harriot

Willebrord Snell