A convex lens has focal length of 30 cm. calculate the what distance should the object be placed from the lens so that it forms an image at 60 cm on the other side of the lens? Find the magnification produced by the lens in this case?

A concave lens has focal length of 15 cm. At what distance should the object from the lens be placed so that it forms an image at 10 cm from the lens? Also find the magnification produced by the lens.

At what distance should be placed from a convex lens of focal length 15 cm to obtain an image three times the size of the object?

A concave lens of focal length 15cm forms an image 10 cm from the lens. How far is the object placed from the lens? Draw ray diagram.

A convex lens of focal length 20 cm is placed at a distance of 24 cm from the screen how far from the lens should an object be placed so as to from a real image on the screen. Also find the nature and magnification of the image produced.

Calculate the distance at which an object should be placed in front of a convex lens of ocal length 10 cm,so as to obtain an image twice the size of the object?

An object is placed at a distance of 1.5 m from a screen and a convex lens is interosed between them .the magnification produced is 4.What is the focal length of the lens?

A convex lens of focal lenth 30 cm and a concave lens of focal length 60 cm are placed in contact.Find the power of the combination.

A double convex lens has 10 cm and 15 cm as its two radii of curvature.The image of an object,placed 30 cm from the lens,is formed at 20 cm from the lens on the other side.Find the refractive index of the material of the lens.Whgat will be the focal length ?What will be the focal length of the lens,if it is immersed in water of refractive index 1.33?