Lenses

• Audi

  10 Aug 09, 13:53

  For the lens used in projector, what happens to the image formed when the converging lens is replaced by a thicker lens?

  Also, should the lower half of the converging lens be covered with a layer of dust, what happens to the image formed?

  Suggest a way to produce a real and upright image on the screen.  Complete the path of the 2  light rays  (I can only get an inverted, but not upright image)

  

  Lots of thanks!!!!!

• eagle

  10 Aug 09, 16:06

  For the lens used in projector, what happens to the image formed when the converging lens is replaced by a thicker lens?

  The image formed will be nearer to the lens because the focal length will be nearer

  And nearer also means the image will still be real and inverted, but smaller than before.

   

   

  Also, should the lower half of the converging lens be covered with a layer of dust, what happens to the image formed?

  The image formed will be dimmer. Reason: Less light rays go through.

   

  Suggest a way to produce a real and upright image on the screen.  Complete the path of the 2  light rays  (I can only get an inverted, but not upright image)

  Add one more lens to invert the inverted image back to upright position ;)

   

  Good luck for your exams :)

• Audi

  11 Aug 09, 22:16

  Thanks eagle for your help. ^^