Light and Reflection

Regular reflection

Regular reflection

reflection of rays on a regular surface

Diffuse reflection

reflection of rays at many scattered angles, on an irregular surface

Difference between real imagine and virtual image

real images are formed through the real intersection of lightrays. virtual images are formed through the imaginary intersection of lightrays.

Concave mirror (focal point)

on the left side

Convex mirror (focal point)

on the right side

Convex mirror (image)

upright, reduced, virtual

Concave mirror (image)

-mostly real, sometimes virtual -upright -enlarged

white light

normal light, when reflected splits and turns into a rainbow

opaque material

forms dark shadows

transparent material

less dark shadow

Umbra

the darkest part of a shadow

Penumbra

half shadow region occurs when light source is partly coved by a screen

incident ray

ray of light that falls on a surface

reflected ray

light ray that is reflected from a surface

i

incidence

r

reflected

normal ray

the ray that is found in the middle of an incident ray and a reflected ray

θi

angle of incidence

θr

angle of reflection

Laws of reflection

angle of incidence is equal to angle of reflection, the normal, incident and reflected rays must be on the same plane and meet on the same point

types of mirrors

plane, convex, concave

plane mirror (image)

virtual, upright, reversed

plane mirror rule

object distance equals to image distance

Real image

appears in from of the mirror (can be projected onto a screen)

Virtual image

appears behind the mirror

ho

object height

hi

image height

do

object distance

di

image distance

F

focal point

2F or C

Center of curvature

Vertex

point at which mirror and principal axis meet

Case 1 : do > 2F (type of image formed + object/image distance)

image formed is reduced, real, inverted, di < do

Case 2: f < do< 2F (type of image formed + object/image distance)

image formed is enlarged, real, inverted, di > do

Case 3: do = F (type of image formed + object/image distance)

no image formed

Case 4: do < F (type of image formed + object/image distance)

upright, enlarged, virtual

magnification formula

hi/ho or -(di/do)

Applications of plane mirrors

kaleidoscope, periscope

v

image distance

u

object distance

In which scenario do concave mirrors form virtual images

when the object is placed in between the focal point (F) and the mirror