Understanding Mirror Reflections: Solving for the Distance of a Third Reflection

[ritwik06]

Homework Statement

The reflecting surfaces of two parallel mirrors are facing each other. They are placed 10cm apart. A light source is placed in middle of the two mirrors. Calculate the distance of the 3rd reflection from the original point source in both the mirrors.

Please tell me how to start!

 

[andrevdh]

Play with the java simulation to see where the virtual images (reflections) are formed.
http://www.phy.ntnu.edu.tw/oldjava/optics/image_e.html"

Notice that each virtual image becomes an "object" that can be reflected from a mirror facing it.

 

[ritwik06]

Play with the java simulation to see where the virtual images (reflections) are formed.
http://www.phy.ntnu.edu.tw/oldjava/optics/image_e.html"

Notice that each virtual image becomes an "object" that can be reflected from a mirror facing it.

Hey the angles don't go less than 18 degree!

 

[andrevdh]

Yes, but see if you can get the basic principle of where the images (reflections are formed). Look at the rays - how do one now where to draw them (in which direction should they be drawn) and where along the ray (what distance along it) to position the image.

 

[ritwik06]

Yes, but see if you can get the basic principle of where the images (reflections are formed). Look at the rays - how do one now where to draw them (in which direction should they be drawn) and where along the ray (what distance along it) to position the image.

The answer is 30cm! Why did you take such long a route to explain. I had to consult the other forum

 

[andrevdh]

The simulation provided you with the opportunity to discover the fundamental principle of image formation for yourself instead of getting the answer from someone else. Working the brain strengthens it and give you more confidence in your own ability thereby reducing stress when it needs to solve future problems (exams). If you showed some attempt at working the problem I would have given you more guidance.