We say: A shows B a series of objects. B is to tell A whether the object is familiar to him or not. a) The question may be, “Does B know what the objects are?” or b) “Does he recognize the particular object?”
1).   Take the case that B is shown a series of apparatus, — a balance, a thermometer, a spectroscope, etc.
2).   B is shown a pencil, a pen, an inkpot, and a pebble. Or:
3).   Besides familiar objects he is shown an object of which he says, “That looks as though it served some purpose, but I don't know what purpose”.