An infinitely long uniformly distributed line charge Ao along the % axis is shown in Figure 2-1 I. Consider the two symmetrically located charge elements dql and dq2 a distance % above and below the point P, a radial distance r away. Each charge element alone contributes radial and % components to the electric field. However, just as we found in Example 2-1a, the two charge elements together cause equal magnitude but oppositely directed % field components that thus cancelleav· ing only additive radial components: