6. Elemental analysis in XPS is principally based on: a. Characteristic energies of emitted X-Rays after photoelectron ejection b. Characteristic energies of ejected photoelectrons C. Characteristic energies of emitted secondary electrons after photoelectron ejection d. Characteristic X-Ray absorbance 7. Fe (111) binds nitrogen atoms significantly stronger than Ru (0001). On which surface do you expect a lower barrier for Nz dissociation? a. On Ru (0001) b. On Fe (111) C. We can not know because the metal surfaces are very different. 8. The figure shows three fuel cell polarization curves obtained with different anode electrocatalysts A, B, C(same amount and temperature). Which one is the best? Potential(V) 0.4 a. A b. B C. 0.2 00 0.5 3.5 4.0 10 1.5 20 2.5 3.0 Current Density/A cm)