4. An ion of iron has an 26 protons, 30 neutrons, and 23 electrons. What are its atomic number, atornic mass, and net charge? A. atomic number = 26, atomic mass = 56, net charge = 3+
B. atomic number = 26, atomic mass = 56, net charge = 3-
C. atomic number = 30, atomic mass = 56, net charge = 3+
D. atomic number = 56, atomic mass = 26, net charge = 3-

The illuminance of a surface varies inversely with the square of its distance from the light source. if the illuminance of a surface is 120 lumens per square meter when its distance from a certain light source is 6 meters, by how many meters should the distance of the surface from the source be increased to reduce its illuminance to 30 lumens per square meter?