i did on optical pumping and i thought i will be good as there was only one tutor who really knows well about the experiment and yeah. i was 100% right as less questions was asked. i didn't pause too long and by the fact there was a girl before me who paused about 3 minutes and in the end she broke down , i feel good, my bad :) . There was a guy who did on the same topic as i do, and poor him for being asked the questions coming from the things that i pointed out before. i was expecting that question but i didn't prepare the answer as i was planning to use my charm instead of answering. haha. being among the first speaker sometimes gives you the more advantages than you know :D