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Reflection and Refraction of the Light MOB. No. = +917837110934
Light:-
Flow with a speed of 3 x 108 m/
Travel in a straight line
Reflection of Light:- The Phenomena of bending of the light from the polished surface.
Law of Reflection :-
1) Incident angle = Reflected angle
2) Incident ray, Reflected ray and Normal are in same plane.
Light Phenomena
Reflection of Light
Refraction of Light
Reflection and Refraction of the Light MOB. No. = +917837110934
Reflection through Plane mirror:-
Image formed by plane always Virtual , Erect , and Inverted
Size of image is equal to the size of Object
The image formed is as far behind the mirror as the object is in front of it.
Spherical Mirrors :- Are of two types depending on the reflecting surface
Concave mirror Convex mirror
Reflecting surface is curved inward Reflecting surface is curved outward
Centre of curvature lie in front of reflecting surface Centre of curvature lie behind of reflecting surface
Focus of Concave mirror lies in front of reflecting surface and always Negative
Focus of Convex mirror lies behind of reflecting surface and always Positive
Image mostly formed is Real and inverted, only in one case when object b/w P and F image formed is Virtual and erect.
Image mostly formed is Virtual and erect, only in one case when object b/w P and F image formed is Real and inverted.
Application :- 1) Torches, Search-lights, Vehicles headlights 2) Shaving mirrors 3) Used by Dentists to see large image of teeth. 4) in solar furnaces to produce heat from sunlight
Application:- 1) used as rear view mirrors in vehicles to see the traffic in erected and diminished image.
Terms of Spherical Mirrors:-
1) Pole (P) :- Centre of the reflecting surface of spherical mirror
2) Centre of Curvature (C):- Centre of sphere of Which spherical mirror forms
Centre of curvature is not part of the mirror
3) Radius of Curvature (R):- Radius of sphere of which the spherical mirror forms
4) Principal axis:- A straight line passing through the pole and centre of curvature
5) Focus(F):- The point of the spherical where all the rays are meet/concentrated after reflecting from spherical
mirrors.
Reflection and Refraction of the Light MOB. No. = +917837110934
6) Focal length (f):- Distance of image from the position of the mirror.
7) Aperture:-The diameter of the reflecting surface of spherical mirror is called aperture.
8) The Radius of curvature is equal to twice of focal length. (R =2f) this implies that the principal focus of a special mirror
lies midway the pole and centre of curvature.
Images formed with respect to Object position in Concave mirror
Reflection and Refraction of the Light MOB. No. = +917837110934
Sr. No
Position of the Object
Position of the image
Size of the image
Nature of the image
Photo
1 At infinity At the focus F Highly
diminished, Pointed sized
Real and inverted
2 Beyond C B/w F and C Diminished Real and inverted
3 At C At C Same size Real and inverted
Reflection and Refraction of the Light MOB. No. = +917837110934
4 B/w C and F Beyond C Enlarged Real and inverted
5 At F At infinity Highly enlarged Real and inverted
6 B/w P and F Behind the
mirror Enlarged
Virtual and erect
Reflection and Refraction of the Light MOB. No. = +917837110934
Images formed with respect to Object position in Convex mirror
Sr. No
Position of the Object
Position of the image
Size of the image
Nature of the image
Photo
1 At infinity At the focus F
behind the mirror
Highly diminished,
Pointed sized
Virtual and Erect
2
B/w infinity and the
pole P of the mirror
B/w P and F, behind the
mirror Diminished
Virtual and Erect
Reflection and Refraction of the Light MOB. No. = +917837110934
Mirror formula and Magnification:-
Mirror formula =
u = distance of object from pole
v = distance of image from pole
Reflection and Refraction of the Light MOB. No. = +917837110934
Refraction of Light:- The Phenomenon in which when light travel from one medium to another medium, the
direction of propagation of light is changed in the second medium is known as Refraction of Light.
Eg. 1) Pencil appear to displaced
2) Coin appear to raised
3) Printed matter on letter appear to raised when thick glass slab is placed over it.
Refraction through Glass slab :-
Law's of Refraction of Light:-
1) The incident ray, the refracted ray and normal all lies in same
Plane and are interfaces at two transparent media at the point of incident.
2) The ratio of sine of angle of incidence to sine of the angle of refraction is
constant and this known as Snell's law of refraction.
This constant value is called the Refractive index
Reflection and Refraction of the Light MOB. No. = +917837110934
Refractive Index :-
Refractive index of Air = 1.0003 if n or µ > (Shows denser medium) Refractive index of Water = 1.33 if n or µ < (Shows rear medium) Refractive index of Glass = 1.52 Refractive index in Ice = 1.31 Refractive index of Ruby = 1.71 Refractive index of Diamond = 2.42
Reflection and Refraction of the Light MOB. No. = +917837110934
Convex Lens Concave Lens Thicker at middle as compared to edges Thicker at the edges than at middle
It is also known as Converging lenses It is also known as Diverging lenses
Image mostly formed is Real and Inverted, only in one case when object b/w F1 and O image formed is Virtual and erect.
Image mostly formed is Virtual and erect.
Application :- 1) Torches, Search-lights, Vehicles headlights 2) Shaving mirrors 3) Used by Dentists to see large image of teeth. 4) in solar furnaces to produce heat from sunlight
Application:- 1) used as rear view mirrors in vehicles to see the traffic in erected and diminished image.
Power of Convex lens is positive (+ve) Power of Cocave lens is positive (-ve)
Sperical Lenses
(A lens made of two spherical surfaces)
Convex Lenses Concave Lenses
Reflection and Refraction of the Light MOB. No. = +917837110934
Images formed with respect to Object position in Convex lens
Sr. No
Position of the Object
Position of the image
Size of the image, Magnification
Nature of the image
Photo
1 At infinity At the focus
F2
Highly diminished,
Pointed sized m<1
Real and inverted
2 Beyond 2F1 B/w F2 and
2F2 Diminished
m<1 Real and inverted
3 At 2F1 At 2F2 Same size
M=1 Real and inverted
Reflection and Refraction of the Light MOB. No. = +917837110934
4 B/w F1 and
2F1 Beyond 2F2
Enlarged m>1
Real and inverted
5 At F1 At infinity
Infinitely large or Highly enlarge
m>1
Real and inverted
6 B/w F1 and
optical centre O
On the same side of the lens as the
object
Enlarged m>1
Virtual and erect
Reflection and Refraction of the Light MOB. No. = +917837110934
Images formed with respect to Object position in Concave lens
Sr. No
Position of the Object
Position of the image
Size of the image
Nature of the image
Photo
1 At infinity At the focus F1
behind the mirror
Highly diminished,
Pointed sized m<1
Virtual and Erect
2
B/w infinity and optical centre O of
the lens
B/w focus F1 and optical
centre O
Diminished m<1
Virtual and Erect
Reflection and Refraction of the Light MOB. No. = +917837110934
Lens formula and magnification:-
Lens formula =
–
u = distance of object from pole
v = distance of image from pole
Magnification:- It is represented by m
Concave lens Magnification always Positive (+ve)
Convex lens Magnification always Negative (-ve)
Power of Lens:- The ability of the lens to converge or diverge the light rays.
It depend on the focal length of the lens Power of the lends reciprocal of the focal length
P =
Power of lens measured in "Dioptre"
Power of Convex lens is positive and that of a Concave lens is negative.
