SCPY152 General Physics II Lecture 1 Ray Optics Udom Robkob, Physics-MUSC June 15, 2015
Today Topics Nature of light Light rays Law of light reflection Law of light refraction Image formation Images from mirrors Images from refractive surfaces
Nature of Light Visible light is electromagnetic waves, in the range of wavelength 400 – 700 nm Light travel in empty space at speed of co = 3x108 m/s In medium light speed is lower to be c, according to electromagnetic properties of the medium. The ratio co/c = n is known as refractive index of the medium
Nature of Light
Nature of Light 4 basic properties will be studied in the following categories: Reflection and refraction ray optics Interference and diffraction wave optics
Light Rays Defined from light path from the source At a distance far from the source, the rays are approximately parallel and will represented with a single ray
Light Reflection Determine reflection of light from smooth reflective surface;
Light Reflection Since abc = abd 1 = ’1 “law of light reflection”
Light Reflection Double reflections
Light Refraction Determine light refraction at smooth refractive surface
Light Refraction Law of light refraction
Light Refraction Nature of refraction
Light Refraction Off set from thin slab
Light Refraction Measuring refractive index of prism, apex angle is
Light Refraction Criterion: min
Critical Angle Total internal reflection – critical angle Water-to –air system
Brewster’s Angle Brewster’s angle
Image Formation Pinhole camera
Images from Mirrors Mirror specification (let light comes from the left hand side) Plane mirror Curved mirrors Concave mirror Convex mirror
Images from Mirrors Image of point object
Images from Mirrors Image magnification Mirror image equation
Images from Mirrors Image magnification Focal point/length Mirror image equation
Images from Mirrors
Images from Mirrors
Images from Mirrors
Images from Refractive Surface Refractive surfaces Convex surface Concave surface
Images from Refractive Surface Image of point object
Images from Refractive Surface Cont. Image equation
Images from Refractive Surface Flat refractive surface – appearing depth
Images from Refractive Surface Concave refractive surface – appearing depth
Images from Refractive Surface Image magnification – from equivalent triangles, we have
Images from Refractive Surface Revisited previous example – what is the image magnification of the coin.