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Geometry/Angle of Incidence and Normals


Hello sir

Sir i know it is not  related to your question . But sir it is indirectly anywhere in mathematics it is related. Sir my question is->  in first law of reflection why normal is drawn sir and what is the use of that angle of reflection and angle of incident
And sir , while reflection  no normal is formed. Then sir what is the use of it.Normal means perpendicular line.

Sir i know that it is not more related because laws of reflection are not in maths they are in physics. But sir, here my doubt is why pupendicular line is drawn called normal and what is the use of angles in laws of reflection.

Sir please dont reply out of my expertise.
Thankyou sir

Hi Aishwaraymeti,

The normal line is a line of reference.  It allows laws like "the angle of incidence is equal to the angle of reflection" to be made very simple, because we measure the angles relative to the normal line.  There is no directionality of the normal line, which makes it easier to use than the edge of the material in calculations and laws.  However, it may be counterintuitive at first because the normal line does not physically exist.



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Azeem Hussain


I welcome your questions on algebra, 2D and 3D geometry, parabolic functions and conic sections, and any other mathematical queries you may have.


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Bachelor of Science, Major Mathematics and Major Economics, McGill University, 2014. Diploma of Collegiate Studies; Pure and Applied Science, Champlain College Saint-Lambert, 2010.

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