A small object is so placed in front of a convex lens of 5cm focal length that a virtual image is formed at a distance of 25 cm. Find the magnification.

An object of height 2 cm is placed in front of a convex lens of focal length 20 cm at a distance of 15 cm from it. Find the position and magnification of the image.

An object of height 1.5 cm is placed on the axis of a convex lens of focal length 25 cm . A real image is formed at a distance of 75 cm from the lens. The size of the image will be

An object is placed in front of a concave mirror at a distance of 7.5 cm from it. If the real image is formed at a distance of 30 cm from the mirror, find the focal length of the mirror. What would be the focal length if the image is virtual.

An object is placed in front of a concave mirror at a distance of 7.5 cm from it. If the real image is formed at a distance of 30 cm from the mirror, find the focal length of the mirror. What would be the focal length if the image is virtual.

An object placed 10 cm in front of a convex lens of focal length 15 cm. The image produced will be

When an object is placed in from of convex lens of focal length f, a virtual image with magnification 2 is formed. Then the object distance is