LUMINOUS\u00a0OBJECTS:<\/strong> These are objects that generate and emit light by themselves. Examples are the sun, stars, fireflies, some deep-sea fishes etc\u2026<\/p>\n NON LUMINOUS OBJECTS:<\/strong> These are objects that depend on luminous objects to illuminate them. We cannot see them until they reflect light from luminous objects. Examples are The moon, road signs, bricks, our bodies, books, clothes etc\u2026<\/p>\n A ray is a direction that lights energy travels. Rays are not real but imaginary lines. A beam is a collection of rays.<\/p>\n PARALLEL BEAM: This is a beam in which the rays are parallel to each other. Searchlights give off parallel beam. DIVERGENT BEAM: This is a beam in which the rays spread from the source. Examples are the sun, lamps, and bulbs produce divergent beams. CONVERGENT BEAM: This is one in which the rays meet at a point. A hand lens produces a convergent beam.<\/p>\n It states that the path of light is reversible and rectilinear propagation of light is the phenomenon of light traveling in a straight line.<\/p>\n Reflection is the bouncing off of light from a surface. When light falls on a surface, three things happen to it;<\/p>\n REGULAR OR SPECULAR REFLECTION: This occurs when parallel rays of light incident on a smooth surface are reflected as parallel rays in one direction. For there to be this kind of reflection, the reflecting surface must be smooth relative to the wavelength of light. IRREGULAR OR DIFFUSED REFLECTION: This is also called scattered reflection. It is a type of reflection in which a parallel rays incident on a rough surface is reflected various directions.<\/p>\n The mirror gives a regular reflection, while the skin, pages of a book and clothes etc\u2026 leads to irregular reflection.<\/p>\n A mirror is a glass made opaque on one side. The image formed by a mirror has the following characteristics. The image is:<\/p>\n There are two types of curved mirrors namely<\/p>\n NOTE:<\/p>\n Where: F = Focus length, V = Image distance, and U = Object distance.<\/p>\n This is the bending of a light ray as it crosses the bonding between two media of different densities thus causing a change in direction.<\/p>\n This is the angle of incidence in the denser medium when the angle of refraction in the less dense medium is 900<\/sup><\/p>\n This occurs when light traveling from a region of a higher refractive index to a region of lower refractive index strikes the boundary at an angle greater than the critical angle such that all light reflects back into the region of the higher refractive index.<\/p>\n OR<\/p>\n Total Internal Reflection is the reflection of an incident ray of light at the interface between the medium of incidence and another medium of a lower refractive index when the angle of incidence in the denser medium exceeds the critical angle.<\/p>\n A lens is a transparent material that is used to focus light and form an image.<\/p>\n A Convex lens is thicker at the center than at the edges. It is also called a Converging lens.<\/strong><\/p>\n A Concave lens is thinner at the center than at the edges. It is also called a Diverging lens.<\/strong><\/p>\n R\u00c9FLEXION DE LA LUMI\u00c8RE La lumi\u00e8re est une forme d'\u00e9nergie qui provoque la sensation de vision. Il existe des sources de lumi\u00e8re naturelles et artificielles. Sources naturelles : Soleil, \u00e9toiles, etc... Sources artificielles : ...<\/p>\nRAYS AND BEAMS<\/h3>\n
TYPES OF BEAMS<\/h3>\n
\n![\"reflection\"](\"https:\/\/i0.wp.com\/www.helpingstudents.com.ng\/wp-content\/uploads\/2017\/11\/parallel-beam.png?resize=157%2C128&ssl=1\")
<\/span><\/p>\n![\"reflection\"](\"https:\/\/i0.wp.com\/www.helpingstudents.com.ng\/wp-content\/uploads\/2017\/11\/light-180x131.jpg?resize=180%2C131&ssl=1\")
<\/span><\/p>\n![\"reflection\"](\"https:\/\/i0.wp.com\/www.helpingstudents.com.ng\/wp-content\/uploads\/2017\/11\/convergent.png?resize=154%2C126&ssl=1\")
<\/span><\/p>\nPRINCIPLE OF REVERSIBILITY OF LIGHT<\/h3>\n
REFLECTION OF LIGHT AT PLAIN SURFACES<\/h3>\n
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TYPES OF REFLECTION<\/h3>\n
![\"reflection\"](\"https:\/\/i0.wp.com\/www.helpingstudents.com.ng\/wp-content\/uploads\/2017\/11\/regular-reflection.png?resize=274%2C232&ssl=1\")
<\/span><\/p>\n![\"reflection\"](\"https:\/\/i0.wp.com\/www.helpingstudents.com.ng\/wp-content\/uploads\/2017\/11\/diffuse-reflection.png?resize=270%2C222&ssl=1\")
<\/span><\/p>\nLAWS OF REFLECTION<\/h3>\n
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IMAGES FORMED BY A PLAIN MIRROR<\/h3>\n
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REFLECTION AT CURVED SURFACES<\/h3>\n
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PARTS OF A MIRROR<\/h3>\n
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REFRACTION OF LIGHT<\/h2>\n
LAWS OF REFRACTION<\/h3>\n
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CRITICAL ANGLE<\/h3>\n
TOTAL INTERNAL REFLECTION<\/h3>\n
APPLICATION OF TOTAL INTERNAL REFLECTION<\/h3>\n
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LENSES<\/h2>\n
TYPES OF LENSES<\/h3>\n
![\"reflection\"](\"https:\/\/i0.wp.com\/www.helpingstudents.com.ng\/wp-content\/uploads\/2017\/11\/convex-vs-concave-lens-300x120.jpg?resize=300%2C120&ssl=1\")
<\/span><\/p>\n![\"reflection\"](\"https:\/\/i0.wp.com\/www.helpingstudents.com.ng\/wp-content\/uploads\/2017\/11\/types-of-lenses-180x180.jpeg?resize=180%2C180&ssl=1\")
<\/span><\/p>\nUSES OF LENSES<\/h3>\n
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LENS DEFECTS<\/h3>\n
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Related Physics Topics<\/h3>\n
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