Archive
10th of March 2017
Physics
Q:

A ray of light passes through a plane boundary separating 2 media,1 and 2 of refractive indices n1=3/2 and n2=4/3.(1) a ray passes fromedium 1 to 2 at an angle of incidence 30.What is angle of refraction at same angle of incidence?(2)if ray passes from medium 2 to 1, what is angle of refraction?

Vikas Mahajan - CBSE - Class X

Friday, March 10, 2017 at 14:29:PM

A:

begin mathsize 12px style Hi space Vikas comma
According space to space Snell apostrophe straight s space law comma
sini over sinr equals straight n subscript straight r over straight n subscript straight i
therefore sinr equals fraction numerator straight n subscript straight i sini over denominator straight n subscript straight r end fraction equals fraction numerator begin display style 3 over 2 end style cross times sin 30 over denominator begin display style 4 over 3 end style end fraction equals 3 over 4 cross times 3 over 4 equals 9 over 16
therefore straight r equals sin to the power of negative 1 end exponent open parentheses 9 over 16 close parentheses equals 34.2 degree

left parenthesis 2 right parenthesis space When space ray space passes space from space medium space 2 space to space 1
sini over sinr equals straight n subscript straight r over straight n subscript straight i
therefore sinr equals fraction numerator straight n subscript straight i sini over denominator straight n subscript straight r end fraction equals fraction numerator begin display style 4 over 3 cross times sin 30 end style over denominator begin display style 3 over 2 end style end fraction equals 4 over 6 cross times 2 over 3 equals 4 over 9
therefore straight r equals sin to the power of negative 1 end exponent open parentheses 4 over 9 close parentheses equals 26.4 degree end style

Friday, March 10, 2017 at 18:24:PM