••10 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 × 10$)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? %3D

••10 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 × 10$)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? %3D