Focal length -physics

bonkysleuth SG

http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=48

Please help me check the unit for the focal length in this virtual lens image. It does not state the unit.thanks.

skythewood SG

focal length unit should be metre, SI unit.

bonkysleuth SG

focal length unit should be metre, SI unit.

thanks. an instruction told me to click on the lens and make focal length shorter. What happens to the shape of the lens?

I found that no matter where I drag the length, focal length remains the same. is there anything I can do to adjust focal length(If you tried the programme, that is)