Unit 6, Chapter 17. CPO Science Foundations of Physics. Unit 6: Light and Optics. Chapter 17 Light and Color. 17.1 Reflection and Refraction 17.2 Mirrors, Lenses, and Images 17.3 Optical Systems. Chapter 17 Objectives.
Foundations of Physics
Chapter 17 Light and Color
The branch of optics that focuses on the creation of images is called geometric optics, because it is based on relationships between angles and lines that describe light rays.17.1 Reflection and Refraction
A converging lens bends light so that the light rays come together to a point.
A diverging lens bends light so it spreads light apart instead of coming together.17.1 Reflection and Refraction
A prism is another optical device that can cause light to change directions.
A prism is a solid piece of glass with flat polished surfaces.17.1 Reflection and Refraction
The incident ray follows the light falling onto the mirror.
The reflected ray follows the light bouncing off the mirror.17.1 Reflection
A surface that is not shiny creates diffuse reflection.
In diffuse reflection, a single ray of light scatters into many directions.17.1 Reflection
Sketch the incident and reflected rays and determine the angle of reflection.17.1 Law of reflection
This bending of light rays is known as refraction.
The light rays from the straw are refracted (or bent) when they cross from water back into air before reaching your eyes.17.1 Refraction
Angle of refraction
Angle of incidence
ni sinQi= nr sin Qr
Index of refraction of incident material
Index of refraction of refractive material
Calculate the angle of refraction for the ray as it enters the water.17.1 Calculate the angle of refraction
Colors between blue and red are bent proportional to their position in the spectrum.17.1 Dispersion and prisms
A rainbow is an example of dispersion in nature.
Tiny rain droplets act as prisms separating the colors in the white light rays from the sun.17.1 Dispersion and prisms
Images are “pictures” of objects that are formed in space where light rays meet.17.2 Mirrors, Lenses, and Images
The image in a mirror is called a virtual image because the light rays do not actually come together.17.2 Mirrors, Lenses, and Images
The distance from the center of the lens to the focal point is called the focal length.
The optical axis usually goes through the center of the lens.17.2 Mirrors, Lenses, and Images
Rays from the same point on an object are bent by the lens so that they appear to come from a much larger object.17.2 The image formed by a lens
These three rays follow the rules for how light rays are bent by the lens:
A light ray passing through the center of the lens is not deflected at all (A).
A light ray parallel to the axis passes through the far focal point (B).
A light ray passing through the near focal point emerges parallel to the axis (C).17.2 Drawing ray diagrams
1 + 1 = 1
do di df