Light Chapter 46

Light Light is a form of energy. Light can do work i.e a solar panel or Crooke’s radiometer. (Light energy can be converted to other forms of energy)

Light Luminous objects are a source of light. i.e. The Sun Non-Luminous objects do not give of their own light. Non-Luminous objects can be seen because light reflects off them.

Luminous vs Non-Luminous

Light Light travels in straight lines. If one piece of card is moved the light can no longer be seen

Light Shadows are formed because light travels in straight lines.

White Light White Light is a mixture of 7 different colours called a spectrum. Richard Red Of Orange York Yellow Gave Green Battle Blue In Indigo Vein Violet

White Light The breaking up of white light is called dispersion. White light can be dispersed using a triangular glass block called a prism.

Reflection Reflection – Light bounces back off surfaces. Light reflects in a regular manner off smooth, shiny, polished surfaces.

Reflection The N is called the normal and is perpendicular to the mirror. Angle A = Angle B

A Periscope A periscope can be used to look around obstacles. The mirrors are positioned in the periscope at a 45o angle.

Refraction Refraction is the bending of light as it passes from one medium to another. Note the light ray gets pulled towards the denser substance. Eg Swimming pool.

A Lens A lens is a piece of glass with a curved surface which is used to bend or refract light.

Concave A concave lens spreads out the rays of light. Diverging lens

Convex A convex lens bends the rays of light together to a point. Converging lens

Uses of Lenses Concave: Convex: Used in glasses to correct short sighted eyes. Convex: Glasses to correct long sighted eyes. Magnifying glasses. Telescopes Cameras Microscopes