Answer:
when the object goes from the focal length to twice the focal length the image goes from infinity to twice the focal length, this image is real and inverted
Explanation:
Let's use the constructor equation to describe the image of a concave mirror
1 / f = 1 / p + 1q
where f is the focal length, p and q the distance to the object and the image, respectively
1 /q = 1/f - 1/p
tell us that the image is between the focal and twice the focal, let's calculate the position of the image
for both ends
case 1, distance to the object p = f
1 / q = 1 / f -1 / f
1 / q = 0
q = ∞
the image is in infinity
case2, distance to object p = 2f
1 / q = 1 / f - 1 / 2f
1 / q = 1 / 2f
q = 2f
the image is twice the focal length, the object and the image are at the same point
therefore the image when the object goes from the focal length to twice the focal length the image goes from infinity to twice the focal length, this image is real and inverted
