A convex lens of focal length 6.25cm is used as a simple microscope. To obtain maximum magnification, the object distance should be

Find the power of a convex lens of focal length 25 cm.

A convex lens of focal length 20 cm is placed at a distance of 30 cm from a screen. Where should an object be placed so as to form its real image on the screen?

A man used a concave lens of focal length 20cm.Find the power of the lens.

An object is placed at a distance of 36 cm from a convex lens of focal length 12 cm. Find the position, nature and magnification of the image. Also, draw a ray diagram.

An object is placed at a distance of 10 cm from a convex lens of focal length 15 cm. Find the position, nature and magnification of the image. Also, draw a ray diagram.

A convex lens of focal length 15 cm is placed in front of a convex mirror co-axially 5 cm from the mirror. The image of an object placed at a distance 20 cm from the lens found to have been formed over the object. Estimate the radius of curvature of the mirror.

An object of 4 cm height is placed in front of a concave lens. An image of size 2 cm is formed at a distance of 15 an from the lens. Find the object distance and the focal length of the lens.