| REFLECTION : REFLECTION 1.Reflection of light
2.Laws of reflection of light
3.Characteristics of image formed by plane mirrors 1 |
| Introduction : Introduction SOURCE-A source of light is an object, from which light is given out. The sources of light are of two kinds-Self luminous and non-luminous
MEDIUM-A medium is a substance through which light propagates or tries to do so. There are three types of media of light.-Transparent,Translucent and opaque.
RAY-A ray of light is the straight line path along which light travels. There are three types of rays-Convergent ,Divergent and parallel. 2 |
| Ray : Ray 3 |
| Reflection of light : Reflection of light Reflection of light is the phenomenon of bouncing back of light in the same medium on striking the surface of any object. In reflection, path of light rays changes without any change in medium.
Reflection is of two types
1.Regular Reflection
2.Irregular Reflection 4 |
| ON-Normal rayAO-incident rayOB-reflected ray : ON-Normal rayAO-incident rayOB-reflected ray i-Angle of incidence
r-Angle of reflection 5 |
| Regular and Irregular reflection : Regular and Irregular reflection 6 |
| Laws of Reflection of light : Laws of Reflection of light According to first law, the incident ray, the reflected ray and the normal ray all lie in the same plane.
According to Second law, the angle of reflection is always equal to the angle of incidence.
These laws of reflection are applicable to all types of reflecting surfaces including spherical surfaces. 7 |
| Characteristics of image formed by plane mirrors : Characteristics of image formed by plane mirrors 1.The image of a real object is always virtual. Such an image cannot be taken on a screen.
2.The image formed in a plane mirror is always erect.i.e.upside of the image is upside of the object and vice-versa.
3.The size of image in a plane mirror is always the same as the size of the object.
4.The image formed in a plane mirror is as far behind the mirror, as the object is in front of the mirror. 8 |
| Cont… : Cont… 5.The image formed in a plane mirror is laterally inverted.i.e. the left side of the object becomes the right side of the image and vice-versa. 9 |
| Spherical Mirrors : Spherical Mirrors A spherical mirror is that mirror whose reflecting surface is a part of a hollow sphere of glass.
Spherical mirrors are of two types:
1.Concave mirrors
2.Convex mirrors 10 |
| Few terms : Few terms Centre of Curvature(C).
Pole (P).
Radius of Curvature (R).
Principal axis.
Principal Focus (F).
Focal length (f).
Aperture. 11 |
| Slide 12 : 12 |
| Relation between f and R : Relation between f and R f=R/2 13 |
| Mirror formula : Mirror formula 1/f=1/u+1/v
f-Focal length
u-object distance
v-image distance 14 |
| Numerical : Numerical 1.Find the focal length of a convex mirror of radius of curvature 1m.
2.An object 4cm in size is placed at a distance of 25.0cm from a concave mirror of focal length 15.0 cm.Find the position, nature and height of the image. 15 |