Thursday, June 19, 2008

Reflection of Light by 2E3 Kho Wei Xian

After the first semester, I have learnt a lot of thing about the reflection of light. The law of reflection, the types of reflection, uses of mirrors and image in a plane mirror.

Reflection is the bouncing off light after hitting a mirror surface. The reflection of light can be represented by the reflected diagram. A plane mirror is a good reflector of light. The ray of light approaching the mirror is known as the incident ray (labeled i in the diagram). The ray of light which leaves the mirror is known as the reflected ray (labeled r in the diagram). At the point of incidence where the ray strikes the mirror, a line can be drawn perpendicular to the surface of the mirror. This line is known as a normal line. (labelled 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. When a ray of light hit a plane mirror and when the light is reflected, the angle of incidence and the angle of reflection is the same. This is called the law of reflection.

I also learnt that in a plane mirror,
The image formed is upright and it is the same size as the object,
The image lies far behind the mirror as the object is in front of the mirror,
The image is laterally inverted
The image is virtual(It cannot be captured on the screen)

There are two types of reflection, Regular and Diffuse reflection.
Regular reflection is when parallel beam of light hits a smooth surface and is reflected as a parallel beam.
Diffuse reflection is when a beam of light hits a rough surface, the individual ray are reflected in different directions. There is image formed in Regular reflection and there is no image formed in Diffuse reflection.

I also learnt the uses of the mirrors. There are three types of mirrors, Plane mirrors, and Convex, Concave mirrors which are under Curved mirrors.

Plane mirrors helps the driver to see traffic behind, make a room appear bigger and let a person check their appearance.

Convex mirrors form upright images that are always smaller than the object. They also allow many things to be seen. Convex mirrors are used in shops for security reasons, and also helps the drivers to see object around the corner.

Concave mirrors form upright magnified images if the object is close to the mirror. The image I inverted if the object is further away. Concave mirrors are used to reflect light into a microscope and help the dentists to check teeth conditions.

I have also found out that other than Regular and Diffuse reflection, there are other types of reflection such as Retro reflection, Complex conjugate reflection, Neutron reflection, Sound reflection, Seismic reflection.

Acknowledgements: http://www.glenbrook.k12.il.us/GBSSCI/PHYS/Class/refln/u13l1c.html
http://en.wikipedia.org/wiki/Reflection_(physics)
Explore Your World With Science Discovery 2

Done By: KHO WEI XIAN (25)

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