Cheatography

# Tahsili Physics (Light) Cheat Sheet by TheGoldenClover

2024 Tahsili Physics: Light

### Light

 Engine­ering optics the study of how light interacts with matter Luminous Flux the measure of the total amount of energy radiated per second from a light source in all directions (measured in lumens (lm) Illumi­nation a measure of the light that falls on a surface (measured in lux (lx)) Illumi­nation Formula E = P/4πr2 (E = illumi­nation, P = luminous flux, r = distance) Diffra­ction the spreading of waves around barriers polari­zation the restri­ction of light to one direction Primary colours RGB

### Charac­ter­istics of Spherical Mirrors

 concave depends on position convex virtual, upright, smaller concave properties infinitely large real, inverted, highly diminished at focus at focus real, inverted, infinitely enlarged (no image) beyond focal point virtual, erect, enlarged image 2x the focal length real, inverted, same size before focal point = inverted and smaller after focal point = erect and larger virtual images cannot be collected on screen

### Spherical Lenses

 convex lens collects light concave lens scatters light Magnif­ication the ratio of the image's length to the object's length Magnif­ication formula M = hi / ho or -di / do ( M is -ive if its real ) 1/f = 1/di + 1/do

### Interf­erence

 interf­erence when two waves superi­mpose to form a wave with a higher or lower amplitude young's double slit experiment explains interf­erence; uses monoch­romatic light to create dark and light bands λ = xd/L

### Reflection Off a Plane

 Reflection Law incident angle = reflected angle Properties of a plane image 1- virtual 2- upright 3- same size 4- horizo­ntally inverted 5- same distance

### Spherical mirrors

 concave mirror collects light rays (used in telescope) convex mirror scatters light rays (sides of cars) Principal Axes center line Focus / focal point the point at which light rays appear to converge Focal Length the distance between the center of the mirror and the focus focal length formula f = r/2 (r = radius of curvature)

### Refraction of Light

 Refraction the bending of light through a medium snell's law n1sinθ1 = n2sinθ2 (n is the refractive index) refraction index n = c/v (c is the speed of light, v is the speed of light in the medium) complete reflection reflection within a medium that occurs when the angle of incidence is greater than the critical angle critical angle the angle of incidence that causes the reflected angle to have 90 degrees complete reflection applic­ations optical fibers mirage an optical illusion caused by a difference in temper­ature that creates refraction rainbow when light is scattered by water droplets

### Sight defects

 farsig­hte­dness (long focal length) corrected with a convex lens nearsi­ght­edness (image forms in front of retina) corrected with concave lens