Question

In a direct vision spectroscope, there are three identical crown glass prisms and two identical flints glass prism. If mean reflective indices of crown glass and flint glass be respectively 1.56 and 1.63 and angle of each crown glass prism be 6, then angle of each flint glass prism should be

• A. $7^o$
• B. $8^o$
• C. $9^o$
• D. ${10}^o$

Answer 1

The correct option is B $8^o$

$(n+1){\delta }_c=\left(n\right){\delta }_f$

$\therefore 3\times 0\cdot 56\times A_c=2\times 0\cdot 63\times A_f$

$\Rightarrow A_f=8^o$