P372-Report.doc

3> Giermin AJ E. Sahagun, LBYPHY3, De la Salle University, Law of Reflection and I mage Formation in Plane Mirror< [footnoteRef:1] [1: ]

Law of Reflection and Image Formation in Plane Mirror (August 2014)Giermin AJ E. Shagun , Bachelor of Science Major in Physics Specialization in Medical InstrumentationDE LA SALLE UNIVERSITYManila, Philippinesgiermin_sahagun@dlsu.edu.phSince the beginning of time ancient mankind use still water from the rivers in order to see their reflection. Reflection is define as the changing the direction back of light in an identical medium after striking a surface. Incident is a ray that strikes to the surface while reflected rays is a ray that rebounds from the surface. The goal of this experiment is to prove the two laws of reflection and to know the how plane mirrors reflected the apparent location of an image and to see the relationship of the image and reflected image. So in this experiment we compare the angle of incidence and angle of reflection both left and right side and in different degrees then as for the image formation in the plane mirror in. In conclusion the relationship of the angle of reflection and angle of incidence is always the same and because no matter the change in degrees of the angle or the change of direction, the angle of reflection and angle of incidence is always the same.

Angle of Reflection, Critical angle , Image, Incidence, Normal, INTRODUCTIONAs you look into a still water , a polished surface or a mirror ,you can see your image or which is called reflection. The reflected image that you see in the mirror or still water will be the same as the object which is being reflected. Mirror is one on the things used to reflect image. The history of mirrors is old as the human race due early humans looking on a still water to see their reflection. But the earliest form of human made mirror was made of polished stone and metal. Bronze or silver mirrors were used by ancient Greeks, Egyptians and Romans. Also brass mirrors was also mentioned in the bible. Then in 1300 mirrors was made of glass plate with mercury or tin. In 1836, Justus von Liebig made a mirror that instead of using mercury he used metallic silver.

Plane mirrors image are virtual, upright, same size as the object, the objected is in front of the mirror is the same distance behind the mirror but it reversed , when the right of the object becomes left of the image or when the left of the object becomes right of the image.

Reflection is define as the changing the direction back of light in an identical medium after striking a surface. Incident is a ray that strikes to the surface while reflected rays is a ray that rebounds from the surface. Then normal is a perpendicular to the surface at the point of incidence and the angle of incidence is the angle between the normal and the incident ray lastly the angle of reflection is the angle that is between the normal and the reflected ray. There two laws of reflection, first angle of incidence must be equal to the angle of reflection and lastly the incident ray, normal and the reflected ray lie in one plane. So in this paper aim to prove the 2 law of reflection and to know the how plane mirrors reflected the apparent location of an image and to see the relationship of the image and reflected image.

Materials and MethodPreparation StageTo do the experiment for the Law of reflection, first gather the following materials: optics bench ray table and base, slit plate, ray optics mirror, light source, component holder, slit mask Then set up the experiment shown in (figure 1.1) then after setting the materials, Turn the light source on and adjust either the light or the plates to produce one straight line of the light. Be sure that the light follows the normal line on the ray table.

(figure 1.1)

Then place the ray optics mirror, aligning the flat surface on the component line. Rotate the table and observe the angle of reflection and incidence and record the measurement. Repeat the same process but this time on the opposite side of the table ray (figure 1.2) and record the data afterwards.

(figure 1.2)

Then to do the experiment in Image formation in a plane mirror, first gather the following materials: optics bench ray table and base, slit plate, ray optics mirror, light source, and component holder in order to conduct the experiment in image formation in a plane mirror. The equipment was set up (sse figure 1.3).

(figure 1.3)

After that, the slit plate and the light source were both adjusted to produce visible rays. After all the adjustments, a blank sheet of white paper was placed on top of the ray table. After doing so, the optics mirror is put on top of the white paper. Adjust the mirror so all of the light rays are reflected. Draw a line on the paper to mark where the flat surface of the mirror is. Using a pencil, mark the two points and label them to avoid confusion. Then remove the paper and reconstruct the rays and lastly draw and label the position of the filament (see figure 1.4).

(Figure 1.4)

ResultsTable I.Angle of incidence vs angle of reflectionAngle of incidence Angle of reflection1(to the left)Angle of reflection 2(to the right)

000

101010

202020

303030

404040

505050

606060

707070

808080

909090

(Graph 1.1)

(Graph 1.2)

DiscussionIn this experiment the angle of incidence and the angle of reflection is equal no matter what degree or direction it may go. The object that is being reflected is also the image will be the image that can be seen and the reason for that is angle of reflection must always be equal to angle of incidence. And the type of reflection that happen in this experiment is called specular reflection, when it is going back it is reflected into one direction thus the light is coming from a one direction.

ConclusionIn conclusion the relationship of the angle of reflection and angle of incidence is always the same because no matter the change in degrees of the angle or the change of direction, the angle of reflection and angle of incidence is always the same.AppendixAcknowledgment I wish to give my gratitude to my lbyphy3 professor for teaching and guiding us throughout the term. I would also like to thank my group mates Alyssa Llanes and Shenelle Dacumos for helping me accomplish this experiments and providing the handouts and camera for the experiments and lastly I would like to give thanks to the laboratory technicians in the physics laboratory for providing the materials for the experiment.

References[1] Fitzpatrick, R. (2007). Law of Reflection. Retrieved from farside: http://farside.ph.utexas.edu/teaching/302l/lectures/node127.html [2] Image Formation for Plane Mirrors. (2014). Retrieved from Physics classroom: http://www.physicsclassroom.com/mmedia/optics/ifpm.cfm[3] Image Formation in a Plane Mirror. (n.d.). Retrieved from De la Salle University: http://www.dlsu.edu.ph/academics/colleges/cos/physics/_pdf/expt-3-image-formation-in-a-plane-mirror.pdf[4] Silverio, A. (2012). Physics: Exploring Life Thourgh Science. Quezon : Pheonix Publishing House .[5] the law of reflection . (n.d.). Retrieved from De la Salle University: http://www.dlsu.edu.ph/academics/colleges/cos/physics/_pdf/expt-4-the-law-of-reflection.pdf [6] The Law of reflection . (2014). Retrieved from Physics classrom: http://www.physicsclassroom.com/class/refln/Lesson-1/The-Law-of-Reflection[7] Tippens, P. (2008). Physics : seventh edition. Boston: Mc Graw Hill.[8] Wagner, D. J. (2004). the law of reflection. Retrieved from Rensselaer Polytechnic Institute: http://www.rpi.edu/dept/phys/ScIT/InformationTransfer/reflrefr/rr_content/reflection_15.html[9] Why is an Image Formed? (2014). Retrieved from Physics Classroom: http://www.physicsclassroom.com/class/refln/Lesson-2/Why-is-an-Image-Formed