http://wiki.answers.com/Q/Why_should_you_use_a_piece_of_lens_paper_only_once"
lens paper is fragile
Lens paper should be used only once to prevent the transfer of dirt, oils, and debris from the paper back onto the lens, which can cause scratches or damage. Reusing lens paper can also lead to the buildup of contaminants that might degrade optical clarity. Additionally, single-use lens paper is designed to be soft and lint-free, ensuring that it effectively cleans without leaving residue or fibers behind. Using it only once helps maintain the integrity and longevity of your lenses.
If you re-use it you will smear oils from your fingers on the lens. Additionally, dust from previously used paper can destroy the coating.
Using lens paper only once helps prevent the transfer of oils, dirt, and debris from the paper back onto the lens, which can scratch or damage its surface. Additionally, single-use lens paper ensures optimal cleanliness and reduces the risk of cross-contaminating different lenses or optical surfaces. Reusing lens paper can lead to ineffective cleaning and potential harm to your lenses.
The height of a piece of paper folded in half once is half of its original height.
When the paper is placed under a magnifying lens, the lens focuses light onto a small spot, raising the temperature. This concentrated heat causes the paper to reach its ignition point, leading to combustion and burning of the paper.
Ink cannot be collected from a piece of paper once it has been applied. Ink is absorbed into the fibers of the paper or dries on the surface, making it difficult to remove without damaging the paper.
into an M-frame? pull the center of the original lens out of the frame from the center, around where the nose piece is. it should come out straight away. to fit a new one in, work the new lens in from the sides of the frame, left and right, once they are in, pop the center of the lens into the frame. et voila.
Do you mean 'How many cats can you draw on a piece of paper'? It depends on your art style and how big you draw them So you mean, 'How many cats can stand/sit/lie on a piece of paper at once'? It depends on the size of the cats, and the size of the paper actually, any answer to your loose question depends on the size of the paper.
When you go to the school, go to the far right, before you see a truck, or after you see a seesaw. There should be a piece of paper in the tree where you jump off the tree into the seesaw. It's kind of hard to see it, but your character will get it once you go over it. ~CoolCuttz12
The stranger wrote "Your exact weight" on a piece of paper
The number of directions that a piece of paper can be folded once without overlap.