| 1 |
Luminous Intensity
Unit for Luminous Intensity
|
Energy per unit time in a cone of unit solid angle
Candela
|
| 2 |
Luminous Flux
Unit for Luminous Flux
|
Energy produced by source of visible light per second
Lumen
|
| 3 |
Illuminance |
Luminous Flux per unit area |
| 4 |
Intensity of illumination from a source of power P on a small area, at a distance r |
I = Pcos θ/4πr2
Where θ is the angle between normal to the area and direction of light
|
| 5 |
Plane mirror |
Can be considered as a curved mirror with infinite radius
Produces virtual image of same size but laterally inverted
|
| 6 |
Number of images formed between two plane mirrors at an angle θ |
(n+1)θ>=360
where n is the smallest integar satisfying the equation
|
| 7 |
Radius of curvature of a curved mirror |
2f |
| 8 |
Sign convention for optics |
All distances are measured from pole i.e. optical center
Distances in the direction of incident light are positive
|
| 9 |
Mirror Formula |
(1/v)+(1/u)=1/f |
| 10 |
Magnification |
m = -v/u
magnification is negative for real images
|
| 11 |
Type of Mirror
|
Nature of Image
|
|
Plane |
virtual image ---- same size ---- erect |
|
Convex |
virtual image ---- diminished ---- erect |
|
concave |
Real ---- inverted ----- diminished or magnified
virtual image ---- magnified ---- erect
|
| 12 |
Reflection and refraction: definitions |
Too basic for revision.. You know it well by now! |
| 13 |
Spherical Mirrors
|
Image Characteristics
|
|
Convex
|
|
Object at infinity |
Image at focus ---- diminished ---- virtual ---- erect |
|
Ibject anywhere between infinity and pole |
Image between focus and pole ---- diminished ---- virtual ---- erect |
|
Concave
|
|
Object at infinity |
Image at focus ---- diminished ---- real ---- inverted |
|
Object beyond C |
Image between f and 2f ---- diminished ---- real ---- inverted |
|
Object at C |
Image at C ---- equal ---- real ---- inverted |
|
Object between C and f |
Image beyond C ---- magnified ---- real ---- inverted |
|
Object at focus |
Image at infinity ---- magnified ---- real ---- inverted |
|
Object between pole and focus |
Image at the back of mirror ---- magnified ---- virtual ---- erect |
| 14 |
Power of lens |
Inverse of focal length (in meters). Unit diopre |
| 15 |
Convex lens ----- positive focal length |
Concave lens ---- negative focal length |
| 16 |
Combined foal length
Two lenses separated by distance d
|
1/F = (1/f1)+(1/f2)-(d/f1f2) |
| 17 |
Few more things you should look at: |
* Magnification, resolvable distance, resolvable angle of:
Simple Microscope
Compound Microscope
Telescope
* Total internal reflection
* Refractive index --- how light behaves in refraction
|
The topics covered in this section are written in a language to cover more important concepts in minimum time.
