Question

To remove chromatic aberration and spherical aberrations relation between $f_1,f_{2}andx$ (assume refractive index of lenses to be equal ) is

• A. $x=f_1-f_2$
• B. $x=\frac{f_1+f_2}{2}$
• C. $x=2f_2,f_1=3f_2$
• D. $x=f_2{f}_1=3f_2$
• E. None of theses

Answer 1

The correct option is C $x=2f_2,f_1=3f_2$

To remove spherical aberration $x=f_1{f}_2$ and to eliminate chromatic aberration
$x=\frac{f_1+f_2}{2}$
Therefore to eliminate both
$x=2f_2$ and
$x=3f_2$