Reflection of light

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ReflectionHammad TariqOptometrist Isra Medical University Islamabad

Contents Reflection

Conditions for reflection

Laws of reflection

Types of reflection

Ophthalmic Use

Luminous & Non-LuminousLuminous objects are those which give of there own light e.g. sun

Non-Luminous objects are those which dont give of the own light e:g moon

Reflection is the change in direction of a wave front between two different media so that the wave front returns into the medium from which it originated When light rays traveling in a medium reaches the boundary of other medium, they turn back to the first medium. This phenomenon of turning back of light into the same medium after striking the boundaryof other medium is called Reflection of Light

Definition

Conditions There should be some incident ray The surface should be polished

Laws The INCIDENT ray, REFLECTED ray and the NORMAL all lies in the same PLANE

Angle of INCIDENT is always EQUAL to angle of REFLECTION

REFLECTED ray is always OPPOSITE to INCIDENT ray

TypesReflection is categorized into which is as follows Specular ReflectionDiffuse Reflection

Specular ReflectionIf the reflecting surface is smooth the REFLECTION thought it will be called SPECULAR reflection

Specular Reflection

Specular Reflection

Diffuse ReflectionWhen light strikes surface of non-metallic material it bounces off in all directions by the microscopic irregularities this is called diffuse reflection Or

If the reflecting surface is rough the reflection thought it will be called diffuse refection

Diffuse Reflection

Ophthalmic UseThe anterior surface of cornea acts as a convex mirror.It is used such by the standard instruments (Keratometer)

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