Question

With the use of _______ chromatic aberrations and other imperfections of the lenses are minimized.

(a) Lenses

(b) Mirrors

(c) Slits

(d) Diaphragm

The question was posed to me in an interview for internship.

This question is from Methods of Monitoring Foetal Heart Rate topic in section Foetal Monitoring Instruments of Biomedical Instrumentation

Answer 1

Correct option is (b) Mirrors

The explanation is: To minimize light losses, lenses are sometimes replaced by front-surfaced mirrors to focus or collimate light beam in absorption instruments. Mirrors are aluminized on their front surfaces. With the use of mirrors, chromatic aberrations and other imperfections of the lenses are minimized.