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Ray Model of Light

This document discusses the ray model of light. It explains that light travels in straight lines called rays, and can be reflected or refracted when it hits an object. Reflection is when light bounces off a surface, following the laws that the angle of incidence equals the angle of reflection. Refraction is when light changes speed and bends as it passes from one transparent medium to another of different density. Refraction causes effects like making underwater objects appear at a different depth than their actual position.

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WEI SHANGLI STANLEY NGAI
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287 views1 page

Ray Model of Light

This document discusses the ray model of light. It explains that light travels in straight lines called rays, and can be reflected or refracted when it hits an object. Reflection is when light bounces off a surface, following the laws that the angle of incidence equals the angle of reflection. Refraction is when light changes speed and bends as it passes from one transparent medium to another of different density. Refraction causes effects like making underwater objects appear at a different depth than their actual position.

Uploaded by

WEI SHANGLI STANLEY NGAI
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PDF, TXT or read online on Scribd
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Ray

Model of Light
Saturday, 29 February 2020 4:22 PM

Light
• Light is a form of energy that enables you to see
• It travels in vacuum at a speed of 3 x 1000000 m/s
• Sound travels in air with a speed of 300 m/s.
• Light travels in straight lines
• Light energy travels along paths are called rays
• A bundle of rays is called a beam of light
• When light hit an object , it can be reflected or refracted

Reflection
• Reflection is the bouncing of light off an opaque surface
• In reflection of light , they are:
—Incident ray: light ray goes towards the surface
—Reflected ray: light ray bounces off the surface
—Angle of incidence (i)
—Angle of reflection [r]

• There are two types of reflection :

Type of reflection Type of surface Image


Image formed
1.Regular reflection

Smooth,polished
surface


2.Diffused reflection No image formed

Uneven,rough surface

Two Laws of regular reflection

• Angle of incidence (i) is equal to angle of reflection [r]


• The incident ray, the reflected ray and the normal lie in the same plane.

Image formed in plane mirror


• Characteristics of imaged formed by plane mirror are:
—upright
—virtual(cannot be focused on a screen)
—laterally inverted (right becomes left)
—same size to the object
—distance of image behind the mirror is the same as the distance of object in front it

Types of mirrors
• The table below shows the application of different types of mirrors.
Type of Application
mirror
Plane mirror • Plane mirror is used to check one another appearance
• Plane mirror are used in cars as rear-view or side view mirrors
• Plane mirror are used to make a room appear more spacious

Convex mirror • Convex mirror is used in shops to spot for thief

• A concave blind corner mirror allows driver to see around the corner of
the road

Concave mirror • Concave mirror is used for dentist to get a magnified image of the tooth

Refraction
• Refraction Is the bending of light rays as it travels from one transparents medium to
another transparent medium
• The refraction is caused by the change in the speed of light rays when travels in the
medium of different densities
• Comparing the density of glass, water and air:
—Glass is the densest , followed by water and air least dense
• When the light travels from a denser medium to a less dense medium, it bend away from
the normal. [angle incidence<angle of refraction]
• When light travels from a less dense medium to a denser medium , it bends towards the
normal. [angle of incidence>angle of refraction]

Effects of refraction : Apparent depth and real depth


• Dues to the refraction of light , an object under the water appears shallow water
• Real depth is the actual position of object under the water
• Apparent depth is the perceived position of the object by eye due to the refraction of light
• The apparent depth is less than its real depth

Dispersion of white light


• Sunlight composed of different colours through it appears white.
• A prism is used to separate seven colours in white lights.
• The seven colour are red , blue , green ,indigo, yellow , orange and violet
• The splitting of white light into its seven colours is called dispersion
• Dispersion of white light is due to light rays are refracted at different angles.
Red rays bend the least and violet rays bend the most

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