m50d's Journal: There was a wrong question on my physics paper

I'm sure of it. Today's (16th June) OCR A level physics paper, the Field and Particle physics one, question 11b. Very much a schoolboy error - the question setter had used nanograms and then assumed that meant *10^-9 in formulae. Unfortunately, thanks to a historical quirk related to the french revolution, the kilogram is actually the base unit, so nanograms are *10^-12. Anyone else notice this? More to the point, anyone know what happens about it? Should I complain to the exam board? How are such things marked? Or did I do something stupid and there's another explanation.