Question

To minimize the spherical aberration choose the correct option among the following :

• A. Using the combination of Plano convex lenses with separation equal to $\frac{f_1+f_2}{2}$.
• B. Using crossed lens with condition$\frac{R_1}{R_2}=-\frac{1}{2}$ for $\mu =1.5$.
• C. Focusing the incident light on more curved surface of Plano convex lens.
• D. Focusing the incident light on plane surface of Plano convex lens.

Answer 1

Answer: (C)

Focusing the incident light on more curved surface of Plano convex lens.

If the plane surface faces the incident rays, the spherical aberration is much larger than that in the case when the curved surface faces the incident rays. In the former case, the total deviation occurs at a single surface whereas it is distributed at both the surfaces in the latter case. Spherical aberration is less if the total deviation of the rays is distributed over the two surfaces of the lens. So, focusing the incident light on more curved surface of plane convex lens minimizes the spherical aberration.