suppose the filament of a bulb is replaced with a filament of the same material, but is twice as long and has twice the diameter, how will this change the brightness of the bulb, if it is connected to the same battery as it was before?

What is the thinnest soap film (excluding the case of zero thickness) that appears black when illuminated with light with a wavelength of 480 ? the index of refraction of the film is 1.34, and there is air on both sides of the film. express your answer in nanometers. hint 1. how to approach th