Explain the construction and working of a compound microscope with a neat diagram.
How to lay out the answer. Follow the frame, then write it in your own words.
1 · Open in one line. A compound microscope uses two convex lenses to give a large magnification of tiny objects.
2 · Construction. Objective: short focal length, near the object. Eyepiece: longer focal length and larger aperture, near the eye. Both are fixed in a tube.
3 · Working.
The object is placed just beyond the focus of the objective.
The objective forms a real, inverted, magnified image.
The eyepiece magnifies it into a virtual, enlarged final image, erect compared with the first image.
4 · Draw the ray diagram. [Diagram: object AB, objective, real image A′B′, eyepiece, final virtual image A″B″ traced with dotted lines]
5 · Magnification. It magnifies in two stages, so it magnifies much more than a simple microscope.
6 · Real-life link. Used in labs to see blood cells, bacteria and malaria parasites.
7 · Close in one line. Magnifying in two stages lets us see objects far too small for the naked eye.
Scoring tip: Label the objective, the eyepiece, both images and the final image as virtual. Use dotted lines for the virtual image.
