Geometric optics

Definition

Geometric optics is the study of light as rays that travel in straight lines and interact with surfaces according to the laws of reflection and refraction. It simplifies complex wave phenomena by ignoring diffraction and interference.

5 Must Know Facts For Your Next Test

1. Geometric optics assumes that light travels in straight lines, which is a valid approximation when the wavelength of light is much smaller than the size of obstacles or apertures it encounters.
2. The law of reflection states that the angle of incidence equals the angle of reflection, measured relative to the normal at the point of incidence on a reflective surface.
3. Snell's Law describes how light bends when passing between different media; it is given by $n_1 \sin \theta_1 = n_2 \sin \theta_2$, where $n$ represents the refractive index.
4. Total internal reflection occurs when light attempts to move from a medium with a higher refractive index to one with a lower refractive index at an angle greater than the critical angle.
5. Thin lens equations relate object distance ($d_o$), image distance ($d_i$), and focal length ($f$) through $\frac{1}{f} = \frac{1}{d_o} + \frac{1}{d_i}$.

Review Questions

• What does Snell's Law state about the relationship between angles of incidence and refraction?
• How do you calculate the critical angle for total internal reflection?
• What are the key differences between convex and concave lenses in terms of image formation?

Related terms

Reflection: The change in direction of a light ray when it bounces off a surface, following the law of reflection.

Refraction: The bending of light as it passes from one medium to another with different refractive indices, described by Snell's Law.

Lens: A transparent optical device used to converge or diverge transmitted light and form images, characterized by its focal length.