Question

When the image is erect magnified and become inverted on moving the mirror away from the object yhe mirror is a blanke mirror

Answer 1

No, the mirror is not plane mirror. The mirror is concave mirror.

This is because in a plane mirror, the image is never magnified, but always the same size as the object. Also, no matter where the object is kept, the image is always laterally inverted but erect.

Also, in convex mirror, the image is always erect but diminished. The image is never magnified in convex mirror.

In concave mirror, the image can be erect and magnified as well as inverted depending on the position of the object. The image is erect and magnified when the object is placed in between F (focus) and P (pole) of the mirror. When moving the object back, the image becomes inverted. Hence, the given mirror is concave mirror.