Question

What are the advantages of a total reflecting prism over a plane mirror in a periscope?

Answer 1

1. It does not requie silvering. 

2. The reflection of light is 100%. 

3. Multiple reflections do not take place in a reflecting prism. Due to this, only one image is formed, which is very bright. 

4. A reflecting prism is free from the trouble arising out of vanishing of the silvering of mirror with the passage of time. 

Answer 2

1.The images are clear and bright.
2.With a prism several reflections of a ray are obtained.
3.Prisms can easily be fastened and built into instruments.
4.The angle between the reflecting surfaces is fixed.
5.The reflecting surfaces are not subjected to wear.