An object is placed so that the image formed is a real image of the same size as the object. what is the position of the object?
a.
b.
c.
d.
at the focal point
at a distance of twice the focal length
greater than the focal length but less than twice the focal length
at a distance less than the focal length

Option(b)

The position of the object  placed so that the image formed is a real image of the same size as the object is at a distance of twice the focal length

Explanation:

In this case, if the object is to be placed in such a way that the image thus formed by the object is real image of the same size so, the position of the object is at a distance  twice  of the focal length .

So the object is  said to be in position at a distance of two times of its focal length  i.e., it can be represented as 2f

luster is not a good characteristic to use by itself because luster is the property of minerals that indicates how much the surface of a mineral reflects light. the luster of a mineral is affected by the brilliance of the light used to observe the mineral surface.