## Thursday, March 12, 2020

### Light Essays

Light Essays Light Essay Light Essay Light BY humza8675 Below there are three objects a mirror, a glass block and a prism, it shows and tells you underneath each of the objects picture a description of what happens when light ray is shone on it. The source of light is a light bulb from a ray box. If a beam of light of one colour is shone through a prism, the direction of the beam is changed by the prism. This is because the two faces of the prism through which the light passes are not parallel. If white light is used the prism splits up the light into a series of colours. This shows hat white light is actually made up of many other colours a fact first shown by Newton in 1666. The spread of colour is called a spectrum. The dispersion of white light into a spectrum occurs because the different colours are refracted by different amounts by the glass of the prism. Violet light is refracted most by a prism and red light is refracted least. The colours of the spectrum are red, orange, yellow, green, blue, indigo and violet. The source of light is a light bulb from a ray box. If you shine a beam of light through the air, it will travel in a straight line. Rays of light usually travel in straight lines until they hit something. If a ray of light hits the surface of a sheet of glass, some light will be reflected by the surface of the glass. However, much of the light will pass through the glass, because glass is transparent. When a ray passes from air into glass the direction in which the light ray is travelling changes. The light ray appears to bend as it as it passes through the surface of the glass. This bending of a ray of light when it passes from one substance into another substance is called refraction. Glass is thicker and heavier than air. If the light slows down when it passes from the less dense air into the denser glass, this slowing down of the ray of light also causes the ray of light to change direction. It is the change in the speed of the light that causes refraction. This is a bit like when a car goes partly off the road and some of the wheels go into the softer edge of the road. The softer surface drags on the wheels and slows them down. This can cause the car to pull to the left, slightly changing its direction. When a ray of light passes from a less dense aterial (e. . air) into a denser material (e. g. glass) it is bent away from the surface between the two materials. This means that in this situation the angle of refraction is always less than the angle of incidence. However, if the ray of light hits the surface at right angles (i. e. at 900) to the surface, the ray is not bent. When a ray of light passes from a denser material (e. g. glass) into a less dense materia l (e. g. air) it is bent towards the surface between the two materials. This means that in this situation the angle of refraction is always greater nan tne angle 0T Inclaence. Light is known to behave in a very predictable manner. The source of light is a light bulb from a ray box. If a ray of light could be observed approaching and reflecting off of a flat mirror, then the behavior of the light as it reflects would follow a predictable law known as the law of reflection. The diagram below illustrates the law of reflection. In the diagram, the ray of light approaching the mirror is known as the incident ray (labeled I in the diagram). The ray of light that leaves the mirror is known as the reflected ray (labeled R in the diagram). At the point of incidence where the ray hits the mirror, a line can be drawn perpendicular to the surface of the mirror. This line is known as a normal line (labeled N in the diagram). The normal line divides the angle between the incident ray and the reflected ray into two equal angles. The angle between the incident ray and the normal is known as the angle of incidence. The angle between the reflected ray and the normal is known as the angle of reflection. The law of reflection states that when a ray of light reflects Offa surface, the angle of incidence is equal to the angle of reflection.