I)with the aid of an appropriate diagram, explain the various signals which are generated when a focused beam of electrons strikes the surface of a polished section. what are each of these signals used for in mineral analysis? ii explain the origin of back-scattered (be) electrons and why they are particularly useful in analysing minerals a gold ore contains native gold, pyrite and quartz. explain how you would distinguish them on an sem screen using be electrons. i) what is the difference between characteristic x-rays and background radiation (bremmstrahlung)? explain the origin of ka, kb and la x-rays

Momentum lab this lab uses a phet simulation. navigate to the phet momentum simulation. if you don’t see the image below when you click on the link, then you need to either enable adobe flash (click on the puzzle piece on your screen) or you need to install adobe flash (this is a free program). change the vectors to be momentum vectors only. they are yellow. make the mass of both balls the same. hit play and notice what happens to the momentum vectors before and after the collision. you might want to play the sim multiple times. click on restart or return balls to start over. to see numbers, check the show values box (inside the green box). red’s momentum vector before the collision is green’s momentum vector after the collision. question 1 options: shorter than longer than equal to question 2 (1 point) saved since green bounces off red, this must be an collision. question 2 options: explosion inelastic elastic question 3 (1 point) red transfers of its momentum to green during the collision. question 3 options: little all most none question 4 (4 points) why does red transfer all its momentum to green? back up your answer with information from the simulation. write at least 2 sentences.