7. What three kinds of structural metals or alloys does “light metals” usually mainly include? Please write down the structure, properties and applications of these three metals. (10%)

6. The electrical conductivity and electron mobility for aluminum areand 0.0012 m2 /V●s, respectively. Calculate the Hall voltage for an aluminum specimen that is 15 mm thick for a current of 25 A and a magnetic field of 0.6 tesla (imposed in a direction perpendicular to the current). (10%)