Geometric Optics
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The document discusses key concepts in geometric optics including: 1) The law of reflection states that the angle of incidence equals the angle of reflection and the incident, normal, and reflected rays all lie in the same plane. 2) Refraction is the bending of light that occurs when passing from one medium to another due to a change in speed. Snell's law describes the relationship between angles of incidence and refraction. 3) Prisms can disperse or separate white light into visible colors due to different wavelengths refracting at different angles according to their frequency.
Geometric Optics
- 1. Geometric Optics Sarah & Emma
- 2. i. Law of Reflection Angle of incidence = angle of reflection Incident ray, reflected ray and normal line all lie on same plane
- 3. Mirror Reflected ray Normal line Incident ray Object Angles of incidence Angles of refraction Source: ppt
- 4. Specular vs. Diffuse reflection Specular reflection reflection off smooth surface (i.e. mirror) Diffuse reflection reflection off rough surfaces (i.e. asphalt)
- 5. A rough surface diffuses light because every individual light ray hits a point of the surface that is oriented at a different angle. This means they will reflect at all different angles. Source: http://www.physicsclassroom.com/class/refln/U13L1d.cfm
- 6. ii. Refraction Bending of light light bends when it passes from one medium to another The boundaries where refraction takes place are called interfaces Glass interfaces Light
- 7. nglass=speed of light in vacuum/ speed of light in glass speed of light in air/speed of light in glass These two index of refractions are the same to 3 sig figs
- 8. Snells Law For a given substance, the ratio sin(angle of incidence)/sin(angle of refraction) is a constant Angle of incidence (慮air) Angle of refraction (慮glass) Normal line Light
- 9. Angle of incidence (慮air) Angle of refraction (慮glass) Normal line Light nglass = sin慮vacuum/sin慮glass = vvacuum/vglass sin慮air/sin慮glass = vair/vglass
- 10. If we add a substance other than air (glass & water instead of air & water) 慮glass Glass Water 慮water nXsin慮X = nysin慮y= nzsin慮z = as long as the interfaces are parallel
- 11. The denser the substance, the greater the index of refraction As light goes from less dense to denser, it bends toward the normal (angle of incidence > angle of refraction) As light goes from denser to less dense, it bends away from normal (angle of incidence < angle of refraction)
- 12. iii. Prism Dispersion separation of visible light into its different colors Angle of deviation overall refraction caused by passage of light ray through prism
- 13. Dispersion Different colored lights have different frequencies Therefore they travel through material w/ different speeds This leads to different angles of refraction and the dispersion of light
- 14. Deviation Angle of deviation angle b/w incident ray and refracted ray that leaves prism 慮blue 慮red