I wonder if it is the place to ask for advice on graduate school statements of purpose but I assumed that SOPs were, in good approximation, written like essays submitted for admission purposes. And so I'm applying for York University MSc in physics.
The SOP, as understood by York U, asks questions similar to college essays on that board: why York U? Why choose a specific topic? What objectives do you want to pursue on the short and long terms and how do you think that program will help you achieve those goals?