Light and Colors

• The color of an object is determined by the wavelengths that are reflected from its surface.
• Sunlight may appear white, but it is actually made up of different colors of light.
• The colors of light are; red, orange, yellow, green, blue, indigo, and violet (ROVYGBIV).
• A rainbow is formed when sunlight is dispersed by the tiny raindrops in the air.
• Violet light slows down the most and is refracted the most while red light slows down the least and is refracted the least.
• Our eyes can detect the colors emitted or reflected from the objects around us.
• The surface at the back of the eye is called the retina.
• The human eye contains three types of receptors called cones.
• Each type of cone is sensitive to red, green, and blue light.
• The rods only let us see things in black, white and grey.
• Our cones only work when the light is bright enough, but not when light is very dim.
• A photoreceptor is a special cell in the eye that responds to light.
• Red, blue and green are the primary colors of light.
• Mixing the three primary colors of light produces white light.
• Mixing the two primary colors produces secondary colors – cyan, yellow, and magenta.
• A luminous object appears the color of the light it is emitting.
• A non-luminous object appears in a certain color because it reflects that color light into your eyes.
• An object reflects the color it is and absorbs all the other colors.
• Lenses have one or more curved surfaces and are used for refracting light.
• Light can be both a wave or particle, depending on the wavelength of the light.
• Light is a form of energy which can be detected by our eyes
• It can travel from one place to another through a media or vacuum
• Light travels at a speed of 3.00x10^8 m/s
• Sound travels at a speed of 330m/s
• The denser an object is the slower light goes through it
• Light travels in a straight line
• Transparent materials allow almost all the light to pass through them.
• Translucent material allow some light to pass through them
• Opaque materials dont allow any light to pass through them
• When light hits the surface of another medium it bounces off or is reflected
• Reflection from a smooth surface is called regular reflection
• Parallel rays = parallel reflected rays
• Non-parallel = converging or diverging reflected rays
• When parallel rays fall on a rough & uneven surface the light reflected rays become scatered
• Incidence ray = ray striking the surface
• reflected ray = ray being reflected
• angle of incidence = angle of reflection
• the normal is the 90 degree angle from the surface