prove that while refraction through a rectangular glass slab the incident ray is parallel to the emergent ray

Asked by  | 11th Mar, 2013, 06:49: PM

Expert Answer:

 
In triangle GBC, r1+90-r2=90 ...as the sum of angles in a triangle is 180 degree
 r1=r2............................i
now refractive index of glass=sin i/sin r1 =sin e/sin r2....................ii   
 
as r1=r2from (i)
 
so i=e .................iii
 
now as the incident ray is extended till E, angle LDE  should be equal to i.
 
for, CF and DE, and intercector CD angle BCF(90+e)=angle CDE(90+i) and they are corresponding angle so CF parallel to DE.

Answered by  | 12th Mar, 2013, 11:04: AM

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