Earth's lower atmosphere contains negative and positive ions that are produced by radioactive elements in the soil and cosmic rays from space. In a certain region, the atmospheric electric field strength is 154 V/m and the field is directed vertically down. This field causes singly charged positive ions, at a density of 802 cm-3, to drift downward and singly charged negative ions, at a density of 719 cm-3, to drift upward (see the figure). The measured conductivity of the air in that region is 2.13 × 10-14 (Ω-m)-1. Calculate (a) the magnitude of the current density and (b) the ion drift speed, assumed to be the same for positive and negative ions.

Earth's lower atmosphere contains negative and positive ions that are produced by radioactive elements in the soil and cosmic rays from space. In a certain region, the atmospheric electric field strength is 154 V/m and the field is directed vertically down. This field causes singly charged positive ions, at a density of 802 cm-3, to drift downward and singly charged negative ions, at a density of 719 cm-3, to drift upward (see the figure). The measured conductivity of the air in that region is 2.13 × 10-14 (Ω-m)-1. Calculate (a) the magnitude of the current density and (b) the ion drift speed, assumed to be the same for positive and negative ions.