Matter, Antimatter and Einstein’s equation

It is my understanding that when antimatter comes in contact with matter that there is nothing left but pure energy.
And since energy and matter are interchangeable (E=Mc2) doesn’t that mean you are actually left with all matter and no antimatter…

Can light do some mechanical work?

“We know that sound can cause some mechanical work(eg:when we keep our hand in front of a large speaker,we feel something hitting the back of our hand), but why this doesn’t happen with light??” -Manishankar asks.
Link to this post!