Why a point sized object can not be placed on the pole ?If the pole is on the mirror ? -when I asked this question before you had answered me that pole is on the surface of the mirror.

Now think,....for positions like focal point,curvature , youcan keep the object standing exactly on those points , or if it is just a small point or particle we can keep it just at the place where the focus/point of curvature is..☺...now take the case of pole🔜 you can keep anything or any point NEAR the pole(with 0m distance) or anything on the surface where the pole is......But you CANT keep anything IN the POLE😊..... well you could do that if you cut that thin piece of pole (with 0cm thickness) and throw it out and keep ur particle there😁...well thats a bit foolish.☺