Question

The respective angles of the flint and crown glass prisms are $A^{\prime }$ and $A$. They are to be used for dispersion without deviation, then the ratio of their angles $A^{\prime }/A$ will be

• A. $-\frac{({\mu }_y-1)}{({\mu }_y^{\prime }-1)}$
• B. $-\frac{({\mu }_y^{\prime }-1)}{({\mu }_y-1)}$
• C. $({\mu }_y^{\prime }-1)$
• D. $({\mu }_y-1)$

Answer 1

The correct option is A $-\frac{({\mu }_y-1)}{({\mu }_y^{\prime }-1)}$

Since $A({\mu }_y-1)+A{]}^{\prime }({\mu }_y-1)=0$

$\Rightarrow \frac{A^{\prime }}{A}=-\left(\frac{{\mu }_y-1}{{\mu }_{y^{\prime }}-1}\right)$