Chapter 1:Chemical Reaction And Equations
Chapter 2:Acids, Bases and Salts
Chapter 3:Metals and Non-metals
Chapter 4:Carbon and Its Compounds
Chapter 5: Periodic Classification of Elements
Chapter 10: Light Reflection and Refraction
Chapter 11:Human Eye and Colourful World
Light is a form of energy . Light help us to see thing around . we can see non luminous object because they reflect light into our eyes
Reflection Of Light:
The bouncing back the light rays which fall on the surface of an object is called reflection of light
The best metal for reflector of ligth is Silver
iii) A bundle of light ray is called beam of light
Incident ray: The light ray which fall on the surface is known as incident ray
Reflected ray The light ray which bounce back from the surface is know as reflected rays
Normal An imaginary line produce when light ray which fall on the surface is known as normal
Angle of incident rayAn angle produce by incident ray with normal at the point of incidence is know as angle of incident
Angle of reflectionAn angle produce by reflected ray with normal at the point of incidence is know as angle Reflected
Laws of Reflection
i)First Laws of Reflection The incident ray, the normal to the mirror at the
point of incidence
and the reflected ray, all lie in the same plane.
ii)Second Laws of
Reflection The angle of incidence is equal to the angle of reflection
Note: Law of reflection is apply all kind of mirror (plane ,sperical mirror)
Regular reflection When parallel rays remain parallel after reflection in one
direction
Diffuse reflectionA parallel ray of incident light is reflected in different
direction
Real image A images which can be obtain on a screan are know as real image
Virtual image A images which can not be obtain on a screan are know as virtual image
Image formation by a plane mirror
i)The image formed by a plane mirror is always virtual and erect.
ii)Object and image are equidistant from the mirror
iii)The image is laterally inverted.
SPHERICAL MIRRORS:
The mirrors, whose reflecting surfaces
are spherical, are called spherical mirrors. The spherical mirrors are the two type :
i) Concave mirror
Concave mirrorA spherical mirror, whose reflecting surface is curved
inwards,
that is, faces towards the centre of the sphere, is called a concave mirror.
Convex mirrorA spherical mirror whose reflecting surface is curved
outwards, is called
a convex mirror
Pole(P)The centre of the reflecting surface of a spherical mirror is a point called the pole.
Centre of curvature(C)The reflecting surface of a spherical mirror has a centre. This point is called the centre of curvature of the spherical mirror.
ApertureThe diameter of the reflecting surface of spherical mirror is called its aperture.Radius of curvatureThe radius of the sphere of which the reflecting surface of a spherical mirror forms a part, is called the radius of curvature of the mirror
Principal Focus A point on the principlal axis of a spherical mirror where the rays of light parallel to the principal axis meet or appear to meat after the reflection from the mirror
Focal Lenght The distance between principal focus and pole . it is denoted by f
Note: foacl length is equal to half of its radius of curvatureImage Formation by Spherical Mirrors
Representation of Images Formed by Spherical
Mirrors Using Ray Diagrams
Image formation by Concave Mirrors
Uses of concave mirrors
i)Concave mirrors are commonly used in
torches, search-lights and
vehicles headlights to get powerful parallel beams of light
ii) Concave mirrors are
often used as shaving mirrors to see a larger image of the face
iii)Large concave mirrors are
used to concentrate sunlight to produce
heat in solar furnaces
iv). The
dentists use concave mirrors to see large images of the teeth of patients
Image formation by a Convex Mirror
Uses of convex mirrors
i)Convex mirrors are commonly used as
rear-view (wing) mirrors in
vehicles.
ii) Big convex mirror are used as shop and railway station security mirror
Sign Convention for Reflection by Spherical Mirrors
According to Cartesian Sign
Convention
Mirror Formula:
Magnification the ratio of the height of the image to the height of the object are known as magnification
Magnification =
REFRACTION OF LIGHT
The change in direction of light when it pass from one medium to another medium is known as refraction
of light
In case of refraction, The angle of incidence is not equal to angle of refraction
Laws of refraction of light
(i) The incident ray, the refracted ray and
the normal to the
interface of two transparent media at the point of incidence, all
lie in the same plane.
(ii) The ratio of sine of angle of incidence to the sine of angle of
refraction is a constant, for the light of a given colour and for
the given pair of media. This law is also known as Snell’s law of
refraction.
The Refractive IndexThe ratio of the speed of light in medium 1 and the speed of light in medium 2.
n21=Refraction by Spherical Lenses
Image Formation by Lenses
Concave
Image Formation in Lenses Using Ray Diagrams
Convex
Lens Formula
Magnification
Magnification = Power of a Lens (P)
The ability of a lens to converge or diverge
light rays depends on its focal length
SI unit of powerThe SI unit of power of a lens is ‘dioptre’. It is denoted by the letter D.
The power of a convex lens is positive and that of a concave lens is negativeChapter 1:Chemical Reaction And Equations
Chapter 2:Acids, Bases and Salts
Chapter 3:Metals and Non-metals
Chapter 4:Carbon and Its Compounds
Chapter 5: Periodic Classification of Elements
Chapter 10: Light Reflection and Refraction
Chapter 11:Human Eye and Colourful World