Evan's Space

Wonders of Physics

N2007P1Q20 Light – Mirror Image through Periscope


The diagram shows an object O viewed using two mirrors. A person looks into the mirrors as shown. At which position is the image of O seen.periscopeSolutions: Option D

To solve this kind of question, you have to do in stages.

1) Consider the object O and the mirror at the top. The image formed will be equal distance perpendicular to the mirror (follows the 5 characteristics of mirror image). Let the image be O’.

2) Now treat O’ as the new object and consider the mirror at the bottom.  Likewise apply the same principle, the image of O’ is now at position D. Alternatively, a fast and simple way is based on the concept that to our eyes, light seems to travel in straight line. Hence to our eyes, the image of O is directly in front.


5 thoughts on “N2007P1Q20 Light – Mirror Image through Periscope

  1. Haha thanks Ying Chieh.

  2. Please tell from which paper is this question. I checked Nov 2007 P1 and it’s not in that paper

  3. Hey is it virtually latterly inverted

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