Fig. 4a and b. Stokes V amplitude of Fe I 5250.2 Å normalized to its value at the centre of the solar disc, , vs. µ. Plotted are curves for models B, D, E, G and PLA. The line patterns are identified in Table 1. a  Amplitude of raw profiles, b  amplitude of profiles broadened by a macroturbulent velocity of 2  km s^-1.