Name - Alwin M RejiClass – XRoll - 8

Law of reflection of light:i. The angle of incident is equal to the

angle of reflection.ii. The incidence ray, the normal to the

mirror at the point of incidence and the reflected ray, all lie in the same plane.

Law of reflection of light:i. The angle of incident is equal to the

angle of reflection.ii. The incidence ray, the normal to the

mirror at the point of incidence and the reflected ray, all lie in the same plane.

Reflection : It is the process of sending back the incidents light.Reflection : It is the process of sending back the incidents light.

Reflection from a mirror:

Incident ray

Normal

Reflected ray

Angle of incidence Angle of reflection

Mirror

Texture affects reflectionDiffuse reflection (rough)

reflects light in many different directions, Specular reflection (smooth)

reflects light in only one directionSmooth – variations in surface

Texture affects reflectionDiffuse reflection (rough)

reflects light in many different directions, Specular reflection (smooth)

reflects light in only one directionSmooth – variations in surface

Light striking a mirror reflects at the same angle that it struck the mirrorLight striking a mirror reflects at the same angle that it struck the mirror

These law of reflection are applicable to all type of reflecting surfaces including spherical surface. Image formed by a plane mirror is always virtual and erect. The size of the image is equal to that of the object. The image formed is as far behind the mirror as the object is in front of it. It is laterally inverted, i.e., the image is inverted sideways

These law of reflection are applicable to all type of reflecting surfaces including spherical surface. Image formed by a plane mirror is always virtual and erect. The size of the image is equal to that of the object. The image formed is as far behind the mirror as the object is in front of it. It is laterally inverted, i.e., the image is inverted sideways

A spherical mirror, whose reflection surface is curved inwards is called a concave mirror and the one whose reflecting surface is curved outwards is called a convex mirror.

A spherical mirror, whose reflection surface is curved inwards is called a concave mirror and the one whose reflecting surface is curved outwards is called a convex mirror.

Sign of M Orientation of Image Type of Image

+ Upright Virtual

– Inverted Real

• A ray traveling through C will reflect back through C

• A ray traveling through (f) will reflect parallel to the PA

• A ray traveling to the intersection of the PA and the mirror will reflect at the same angle below the PA.

• A ray traveling parallel to PA will reflect through the focal point

• A ray traveling through C will reflect back through C

• A ray traveling through (f) will reflect parallel to the PA

• A ray traveling to the intersection of the PA and the mirror will reflect at the same angle below the PA.

• A ray traveling parallel to PA will reflect through the focal point

Hard Surface

Reflective surface is on the outside of the curve. The points f and C are located behind the mirror

negative

Reflective surface is on the outside of the curve. The points f and C are located behind the mirror

negative

A ray parallel to the PA will reflect directly away from f.A ray towards f will reflect parallel to the PAA ray towards C will reflect directly away from C.A ray to the intersection of PA and mirror will reflect at the same angle below the OA.Trace the 3 diverging lines back through the mirror to reveal the location of the image which is always virtual

A ray parallel to the PA will reflect directly away from f.A ray towards f will reflect parallel to the PAA ray towards C will reflect directly away from C.A ray to the intersection of PA and mirror will reflect at the same angle below the OA.Trace the 3 diverging lines back through the mirror to reveal the location of the image which is always virtual

When a ray of light travels obliquely one medium to another, the direction of propagation of light in the second medium changes. This phenomenon is known as refraction of light.

When a ray of light travels obliquely one medium to another, the direction of propagation of light in the second medium changes. This phenomenon is known as refraction of light.

A good analogy for refracting light is a lawnmower traveling from the sidewalk onto mud

A good analogy for refracting light is a lawnmower traveling from the sidewalk onto mud

The speed of light is different in different media. i.e., refraction is due to change in the speed of light on going from one medium to another.

The speed of light is different in different media. i.e., refraction is due to change in the speed of light on going from one medium to another.

1. The incident ray, the refracted ray and the normal to the interface to two transparent media at the point of incidence, all lie in the same plane.

2. 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 known as Snell's law of refraction. If the angle of incident and r is the angle of refraction then,

This constant value is called the refractive index of the second medium with respect to the first.

1. The incident ray, the refracted ray and the normal to the interface to two transparent media at the point of incidence, all lie in the same plane.

2. 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 known as Snell's law of refraction. If the angle of incident and r is the angle of refraction then,

This constant value is called the refractive index of the second medium with respect to the first.

Converging

Diverging

f- curve of lens & index of refraction

1. Ray parallel to PA, refracts through far focal point

2. Ray through center of lens, continues straight line

3. Ray through near focal point, refracts through lens, continues parallel to PA

Treat lens as though it were a flat plane.

1. Ray parallel to PA, refracts through far focal point

2. Ray through center of lens, continues straight line

3. Ray through near focal point, refracts through lens, continues parallel to PA

Treat lens as though it were a flat plane.

Diverging Lens Diagram

• Because the rays that enter a diverging lens do not intersect a virtual image is formed by tracing back the refracted rays.

• Ray 1 - parallel to PA, refracts away from near f, trace back to near f.

• Ray 2 - ray toward far f, refracts parallel to PA, trace back parallel to PA

• Ray 3 - ray through center, continues straight, trace back toward object

Sign p q F

+Near side of

lensFar side of

lensConverging

Lens

– Far side of

lensNear side of

lensDiverging

Lens

p = 30.0cmf = 10.cmp = 30.0cmf = 10.cm

p = 12.5cmf = -10.0cmp = 12.5cmf = -10.0cm