A concave mirror has a focal length of 20 cm. Find the position or positions of an object for which the image-size is double of the object-size.

A concave mirror has a focal length 20 cm. The distance between the two positions of the object for which the image size is double of the object size is

A concave mirror has a focal length 20 cm. The distance between the two positions of the object for which the image size is double of the object size is

A concave mirrorr has a focal length 20 cm. The distance between the two positions of the object for which the image size is double of the object size is

An object is placed at a distance of 20 cm in front of a concave mirror of focal length 10 cm. Determine the position of the image. What is the ratio of the size of the image to the size of the object ?

The focal length of a concave mirror is 30 cm.Find the position of the object in front of the mirror,so that the image is there times the size of the objects.