Answer those questions

Asample of a gaseous substance changes into a liquid

In positive numbers less than 1, the zeros between the decimal point and a non-zero number are blank significant

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