Totally reflecting prisms are preferred to mirrors in periscopes because
I. mirror gives multiple images
II. silvering on mirrors is easily damaged
III. mirrors reflect less light than totally reflecting prisms
A
I only
B
I and II only
C
I and III only
D
II and III only
E
I,II and III
Verified Correct Answer: E.
Physical Principles & Numerical Solution
Total internal reflection in prisms occurs without loss of light, while mirrors can have some absorption and scattering. Thus, totally reflecting prisms generally reflect more light, and the silvering (reflective coating) on mirrors can be easily scratched or damaged, which makes them less durable than totally reflecting prisms.
An ordinary mirror is that it reflects from both surfaces. giving multiple reflections.
Source: Myschool Past Questions Archive (Record #42814)