Explain the construction and working of a compound microscope with a neat ray - diagram.

Construction: A compound microscope consists of two convex lenses. The lens towards object is called objective lens and the lens near eye is called the eye piece. The focal length of objective lens is less than the focal length of eye piece. This combination forms the magnified image of the object.

The figure below shows the compound microscope.

Working: The object AB is placed in front of objective lens in such a way that its real, inverted and magnified image A’B’ is obtained beyond the centre of curvature of objective lens.

The image A’B’ becomes an object for the eye piece. The position of image is adjusted such that it lies within the focal length of eye piece.

The eye piece forms the virtual, erect and magnified image A”B” of the object.