Reflection of Light 13.2 Karla Mendez and Shelby Bowen
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Reflection of Light 13.2Karla Mendez and Shelby Bowen
Introduction
• In this lesson we are going to talk about what reflection is and the difference between specular and diffuse reflection of light. We will also be applying the law of reflection for flat mirrors and explain and describe images formed by flat mirrors.
Key Words
• Reflection
• Angle of incidence
• Angle of reflection
• Virtual image
• Specular reflection is defined as light reflected from a smooth surface at a defined angle.
• This is an example of specular reflection.
Specular Reflection
Diffuse Reflection
• Diffuse reflection is reflection off of rough surfaces such as clothing, paper, and the asphalt roadway.
• Diffuse reflection originates from a combination of internal scattering of light.
• Diffuse reflection allows us to see most things around us. o Example: Light is diffusely reflected from a paper in
many directions.
Diffuse Reflection
• You can see that the the reflection of the light hitting the rough surface causes
it to scatter in
many different
directions.
What is the Lawof Reflection (flat mirrors)?
• Reflection is when a ray of light strikes a plane mirror, the light ray reflects off the mirror.
• Flat mirrors are the simplest form of a mirrors
• Reflection is a change in direction of the light ray.
• The law states that the angle of incidence is equal to the angle of reflection.
Key words on the Law of Reflection
• Angle of incidence
• Angle of reflection
• Incident ray
• Reflection ray
• “Normal”
What is the angle of incidence?
• Angle of incidence is the angle between a beam incident on a surface and the normal.
• Line perpendicular to the surface at the point of incidence.
● The red line represents the incident ray (sunlight)
● The black line represents the normal
● The angle between the two is called the angle of incidence
What is the angle of reflection?
• The angle between a reflected ray and the normal, drawn at the point of incidence to a reflecting surface.
• Light reflects off a mirror at the same angle as it did when it (incident ray) hit the mirror.
• A mirror can only reflect 90% of incident light.
The distance between the normal (dotted line) and the reflected ray (red line) is the angle of reflection.
Images formed by flat mirrors
-Whats an image?❖ A real image of an object produces the
same pattern of light as the object does somewhere in space.
❖ A virtual image is the apparent position from which a pattern of light reaches our detector, if we make the assumption that it has traveled from its source to the detector along a straight-line path.
Real image
Virtual
The reason why the virtual image looks lighter is because only 90% of the original image is being reflected by the mirror.
What’s in the mirror?
• When you look in the mirror you are looking at a reversed you!
• The image of your left is now on the right and your right is on the left. o Example: When you are brushing your teeth and you
have a shirt on the says Hollister, in the mirror it will be backwards because a mirror reverses the virtual image (image in the mirror) from the original (real image).
The baby’s reflection is reversed. You can see that the baby’s right side of its body is reflected on the left and the left is on the right
Images Formed by flat mirrors continued..
• Mirrors can produce real and virtual images by reflection.
• A flat mirror only produces virtual images.• The Law of Specular Reflection states that
light reflecting from a plane mirror forms an angle to the NORMAL equal to the angle between the normal and the incident light.
Summary● Specular reflection is defined as light
reflected from a smooth surface at a defined angle.
● Diffuse reflection is reflection off of rough surfaces○ clothing, paper, asphalt roadway○ scattering of light○ allows us to see most things
Summary (Continued)
• Reflection is when a ray of light strikes a plane mirroro flat mirrors are the simplest form of mirrors o reflection is a change of reflection in a light ray
• The law of Reflection states that the angle of incidence is equal to the angle of reflection
Summary (Continued)
• Angle of incidence is the angle between a beam incident on a surface and the normal.
• The angle between a reflected ray and the normal, drawn at the point of incidence to a reflecting surface.
Summary (Continued)
• A real image of an object produces the same pattern of light as the object does somewhere in space.o Example: You
• A virtual image is the apparent position from which a pattern of light reaches our detectoro Example: Your reflection in the mirror
Summary (Continued)
• Mirrors can produce real and virtual images by reflection.
• A flat mirror only produces virtual images.o Example: The mirror in your bathroom
Questions?
Bibliography All Things Reflected. (n.d.). Optics For Kids
. Retrieved October 25, 2013, from http://www.optics4kids.org/home/teachersparents/articles/the-reflection-of-light/
Molecular Expressions Microscopy Primer: Light and Color - Reflection of Light: Interactive Java Tutorial. (1998, June 21).
Molecular Expressions Microscopy Primer: Light and Color - Reflection of Light: Interactive Java Tutorial. Retrieved October 25, 2013, from http://micro.magnet.fsu.edu/primer/java/reflection
Reflection of light. (2012, April 18). Science Learning Hub RSS. Retrieved October 25, 2013, from http://www.sciencelearn.org.nz/Contexts/Light-and-Sight/Science-Ideas-and-Concepts/Reflection-of-light