question form

Your 'question form' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.

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The setup of this experiment is similar to that of the preceding experiment, which is posted at your access site under the title '10-26-2009_____activities_prelinimary_to_wave_experiments'.

Here is a copy of the instructions describing the sharply focused band:

For the first part of this lab you will again use the cylindrical lens and candle flame, with a book for your screen.

Typically when the position of the candle flame remains fixed, and you then move the screen behind the lens back and forth, closer to and further from the water-filled cylinder (recall that you used your physics book as a screen in Part 1 of this experiment), the image (i.e., the vertical bright band) on the screen will get wider or narrower. There will be one particular distance at which the band will have its minimum width and sharpest focus.

At that distance the image of the flame will be regarded as 'in focus'.

That distance will be called the 'focused position' for the system.

For different distances of the candle flame from the cylindrical lens, the focused positions will also differ.

However if the source gets too close to the lens (i.e., to the cylinder--the cylinder is acting here as a lens), it is no longer possible to form a sharply focused band.

Let me know if you have specific questions about what you do and do not understand about the description and/or the setup.