 Where should an object be placed in front of a convex lens to get a real image of size of the object. So at the center of the curvature which is also at twice the focal length. The image formed by a concave mirror is observed to be virtual. A virtual image by a concave mirror is possible in only one case. When the object is placed between focus and pole, it acts also and larger than the object cool. Where should the position of the object be between the principal focus and the center of curvature. At the center of curvature, beyond the center between pole and the principal focus. The center is delta.