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Light, reflection, refraction and colors


Author: Subject Coach
Added on: 15th Jan 2017

 
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In this video lesson, we will discuss that Light from a source forms shadows and can be absorbed, reflected and refracted. We will learn about light rays, what opaque, transparent and translucent objects are.

 

Elaborations

  • drawing simple labelled ray diagrams to show the paths of light from a source to our eyes
  • classifying materials as transparent, opaque or translucent based on whether light passes through them or is absorbed
  • recognising that the colour of an object depends on the properties of the object and the colour of the light source
  • recognising the refraction of light at the surfaces of different transparent materials, such as when light travels from air to water or air to glass

 

Author: Subject Coach
Added on: 15th Jan 2017

Please get in touch with your teacher or tutor in case you have a question related to this lesson

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In this part we will discuss about different Mirrors and Their Use

A curved mirror is a mirror with a curved reflecting surface. The surface may be either convex (bulging outward) or concave (bulging inward)

Examples of concave mirrors are Headlights of a car, Dentist Mirror, Make up mirrors

If the surface of a mirror is perfectly flat, what you see in the glass is a reasonable approximation to what's really there—but with one crucial difference: the image appears to be shifted from left to right (inverted) such mirror is flat mirror.

Image is virtual, upright, unmagnified

Rays seem to come from behind the mirror, but, of course, they don't.  It is virtually as if the rays were coming from behind the mirror.

If the mirror bows inward at the center (known as a converging mirror or concave mirror), light rays will appear to come from in front of the mirror, the reflection will be nearer to you, and reflections will appear bigger than they really are. That's why a converging mirror magnifies. Shaving mirrors work like this.

Image is real, inverted, and magnified

In a mirror that bulges outward at the center (a diverging mirror or convex mirror), the opposite happens. Light rays seem to come from behind the mirror and reflections will appear smaller and further away than they would in a plane mirror. Driving mirrors work like this (and so does the back of a spoon if you hold it just right)

Image Is Virtual, Upright, And DE magnified

Convex mirror curves outwards like back of a spoon.
The image reflected from a convex mirror is smaller, upright, and virtual.

The passenger-side mirror on a car is typically a convex mirror. Convex mirrors are preferred in vehicles because they give an upright, though diminished, image. Also they provide a wider field of view as they are curved

They are used to focus light. Unlike convex mirrors, concave mirrors show different image types depending on the distance between the object and the mirror