Punk'd!
Those who study any mathematics related subjects should know that there are tons of formulae to use. And for some examinations, you will have these formulae given to you.
For the physics examination, the prof actually mentioned that formulae will be given so many forumlae were not memorised. So naturally everyone will take a look at the formulae list given for the past year exam papers and note down which isn't given.
Now the funny thing here is that for this year's examination, many of the needed formulae isn't given, and those that are given were not used for the examination.
Damn you Chen Lang!!!