The magnitude J of the current density in a certain lab wire with a circular cross section of radius R ! 2.00 mm is given by J ! (3.00 $ 108)r2, with J in amperes per square meter and radial distance r in meters. What is the current through the outer section bounded by r ! 0.900R and r ! R

What are the factors that affect the resistance of a wire?

How is the gravitational force related to the distance between two objects?

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