Question

A thin prism P₁ with angle 6⁰ and made from glass of refractive index 1.54 is combined with another thin prism P₂ of refractive index 1.72 to produce dispersion without deviation. The angle of prism P₂ will be –

• A. 5⁰ 24'
• B. 4⁰ 30'
• C. 6⁰
• D. 8⁰

Answer 1

Answer: (B)

4⁰ 30'

Answer 2

$\frac { \mathrm { A } ^ { \prime } } { \mathrm { A } }$ = $\frac { ( \mu - 1 ) } { \left( \mu ^ { \prime } - 1 \right) }$ Ž = – $\frac { ( 1.54 - 1 ) } { ( 1.72 - 1 ) }$

Ž A' = – 4.5⁰ = 4⁰30'

Option B is correct.