used to see the tiny objects. It has better magnification power than simple microscope. Magnification power of microscopes can be increased by decreasing the focal length of the lens used. Due to constructional limitations, the focal length of the lens cannot be decreased beyond certain limit.
This problem can be solved by using two separate biconvex lenses. Construction A compound microscope consists of two convex lenses. The lens with the shorter focal length is placed near the object, and is called as ‘objective lens’ or ‘objective piece’. The lens with larger focal length and larger aperture placed near the observer’s eye is called as ‘eye lens’ or ‘eye piece’.
Both the lenses are fixed in a narrow tube with adjustable provision. Working The object (AB) is placed at a distance slightly greater than the focal length of objective lens (u > f o ). A real, inverted and magnified image (A'B ' ) is formed at the other O B A F A B Figure . Image formation in simple microscope Optics side of the objective lens.
This image behaves as the object for the eye lens. The position of the eye lens is adjusted in such a way, that the image (A'B') falls within the principal focus of the eye piece. This eye piece forms a virtual, enlarged and erect image (A " B " ) on the same side of the object Compound microscope has to times more magnification power than simple microscope Travelling Microscope A travelling microscope is one of the best instrument for measuring very small length with high degree of accuracy at the order of .01mm. It works based on the principle of vernier.
Its least count is . mm. . TELESCOPE Have you seen the recent lunar eclipse?
With our naked eye we can’t visualize the phenomena distinctly. Then, how can we see the distant object in clearer manner? It is possible with telescope. Telescope is an optical instrument to see the distant objects.
The first telescope was invented by Johann Lippershey in . Galileo made