Question

Three prisms of crown glass, each have angle of prism `9^(@)` and two prisms of flint glass are used to make direct vision spectroscope. What will be the angle of flint glass prisms if `mu` for flint is `1.69` and `mu` for crown glass is `1.53` ?
A. `11.9^(@)`
B. `16.0^(@)`
C. `15.3^(@)`
D. `9.11^(@)`

Answer 1

Correct Answer - A
Total devittion `=0`
`delta_(1)+delta_(2)+delta_(3)+delta_(4)+delta_(5)=(mu_(1)-1)A_(1)-(mu_(2)-1)A_(2)`
`+(mu_(3)-1)A_(3)-(mu_(4)_1)A_(4)+(mu_(5)-1)A_(5)=0`
`implies2 xx A_(2)(1.6-1)=3(1.53-1)9`
`impliesA_(2)=3((0.53xx9)/(1.2))=11.9^(@)`