Calculating Focal Length Given L & U: Uncertainties Explained

Thread starter math4me
Start date Apr 5, 2004
Tags

Focal Focal length Length Uncertainties

AI Thread Summary

To calculate the focal length (F) given object distance (L) of 60 cm and image distance (U) of 31 cm, use the formula 1/L + 1/U = 1/F. This equation allows you to derive F by substituting the values for L and U. To find uncertainties in the measurements, consider the precision of the distances and apply error propagation methods based on the formula used. Understanding how uncertainties affect the final result is crucial for accurate calculations. Accurate focal length determination is essential in optics applications.

Apr 5, 2004

math4me

I am trying to find F, i have L = 60cm and U = 31cm, how would i calculate f (focal length)?

and also how would i find the uncertainties?

thank you very much

Science news on Phys.org

Apr 5, 2004

Kurdt

Staff Emeritus

Science Advisor

Gold Member

Not sure about the uncertainties but I assume U and L are object and image distances so the formula you need is

\frac{1}{L} + \frac{1}{U} = \frac{1}{F}

Thread 'A quartet of epi-illumination methods'

Well, it took almost 20 years (!!!), but I finally obtained a set of epi-phase microscope objectives (Zeiss). The principles of epi-phase contrast is nearly identical to transillumination phase contrast, but the phase ring is a 1/8 wave retarder rather than a 1/4 wave retarder (because with epi-illumination, the light passes through the ring twice). This method was popular only for a very short period of time before epi-DIC (differential interference contrast) became widely available. So...

View full post »

Thread 'Effective absorption coefficient of gold nanoparticles'

I am currently undertaking a research internship where I am modelling the heating of silicon wafers with a 515 nm femtosecond laser. In order to increase the absorption of the laser into the oxide layer on top of the wafer it was suggested we use gold nanoparticles. I was tasked with modelling the optical properties of a 5nm gold nanoparticle, in particular the absorption cross section, using COMSOL Multiphysics. My model seems to be getting correct values for the absorption coefficient and...

View full post »