Whats the cost of hydroelectric energy per year?
replied to: lauroT
Replied to: Whats the cost of hydroelectric energy per year?
How to Measure magnification
How can I see how strong a magnifying glass is?
I bought this magnifying glass http://www.liangdianup.com/inventory/189901.htm and I want
to know how to test it to see how strong it is. I hear a lot of people talk about
magnifying and how strong the magnification is, but I would like to know the true
magnification of my magnifying glass. I have a few of them and some seem stronger then
others. How can I rate these? How can I pin a correct number on mine? How do the companies
that make these come up with these numbers.