A needle 10 cm long is laced along the axis of a convex lens of focal length 10 cm such that its middle point is at a distance 20 cm from the lens. Find length of the image needle.

A 5 cm long needle lies along the principal axis axis of a concave miror of focal length 20 cm in such a way that the end closer to the pole is 40 cm from it.Find the length of the image of the needle formed by the mirror.

An object is placed at a distance 5 cm from a convex lens of focal lenth 10 cm.Calculate the position nd magnifiation of the image.

The size of the image of an object,which is at infinity, as formed by a convex lens of focal length 30 cm is 2 cm. If a concave lens of focal length 20 cm is placed between the convex lens and the image at a distance of 26 cm from the convex lens, calculate the new size of the image

An object of size 5 cm is placed at distance of 25 cm in front of a convex lens of focal length 20 cm. Find the size and nature of image and its distance from the lens.

A luminous object is placed at a distance of 30 cm from the convex lens of focal length 20 cm.On the other sie of the lens,at what distance from the lens,a convex mirror of radius of curvature 10 cm be placed in order to have an upright imae of the object coincident with it?