How far should an object be placed from a concave mirror of focal length 15 cm so as to get an image magnified two times?

An object is placed in front of a concave mirror of focal length 20 cm and an image of magnification -2 is formed. Find the position of the object and the image. Draw a ray diagram.

Find the position of an object which when placed in front of a concave mirror of focal length 20cm, produces a virtual image, which is twice the size of the object.

An object is placed 30cm away from a concave lens of focal length 15cm. Find the position, size and nature of the image.

An object is placed at a distance of 30cm from a concave mirror of focal length 20 cm. Find the position, nature and the magnification of the image. Draw a ray diagram.

An object is placed at a distance of 10cm from a convex mirror of focal length 15cm. Find the position and nature of the image.

We wish to obtain an erect image of an object, using a concave mirror of focal length 15cm. What should be the range of distance of the object from the mirror? What is the nature of the image? Is the image larger or smaller than the object? Draw a ray diagram to show the image formation in this case.