14. Experiments have shown that when a clean tungsten surface is heated by laser irradiation using a focused ruby laser, the rate of evaporation of tungsten from the surface is similar to that obtained by more conventional surface-heating methods. The following experimental data relates the observed temperature change as a function of laser amplitude. Fit a first-order polynomial to these data.

Laser pulse amplitude 0.7 0.9 1.1 1.2 1.5 1.7 1.9 2.0 2.1 Surface temperature (◦C) 630 740 700 745 1120 1205 1510 1530 1520