1. an air-core coil consists of 10 layers, and each layer is 11cm long and has 400 turns. the average radius of the layers is 2.25 cm. the flux density within the coil can be closely approximated by using the formula: B=µIN/2r which of the following best describes this statement? 1) true always 2)True only if the current flow is relatively small 3)false always 4)false only if the current flow is relatively small .............. 2. flux lines are 1)discrete lines of concentrated magnetic force 2)used only to describe the direction of a magnetic field 3)used only to indicate the magnitude of a magnetic field 4)a tool devised by scientists to aid in analyzing magnetic force my answer is 1 and 2???