Question

_______ are often used for splitting the beam.

(a) Multilayer coated lenses

(b) Silvered films

(c) Silicate glasses

(d) Half-silvered mirrors

I got this question by my school principal while I was bunking the class.

This key question is from Methods of Monitoring Foetal Heart Rate in portion Foetal Monitoring Instruments of Biomedical Instrumentation

Answer 1

The correct choice is (d) Half-silvered mirrors

Explanation: The two beams must retain the spectral properties of the incident beam. Half-silvered mirrors are often used for splitting the beam. However, they absorb some of the light in the thin metallic coating. Beam splitting can also be achieved by using a prismatic mirror or stack of thin horizontal glass plates, silvered on their edges and alternatively oriented to the incident beam.