Question

With the help of a ray diagram, describe the construction and working of a compound microscope.

Hint:

Compound microscope facts:

Two convex lenses
Objective → real image
Eyepiece → virtual magnified image
Final image is inverted

Answer 1

Construction and Working of a Compound Microscope
A compound microscope is an optical instrument used to view very small objects by magnifying them. It consists of two convex lenses: the objective lens and the eyepiece (ocular) lens, mounted in a tube.

Construction:
1. Objective Lens (O): A convex lens with a short focal length placed close to the object.
2. Eyepiece (E): A convex lens with a longer focal length, used to magnify the image formed by the objective lens.
3. Stage: Platform where the object is placed.
4. Body Tube: Maintains proper distance between the lenses.
5. Light Source / Mirror: Provides illumination for viewing.

- The object is placed just beyond the focal point of the objective lens.
- The objective lens forms a real, inverted, and magnified image of the object at point I1.
- The eyepiece lens acts as a simple magnifier for the image I1. The final image I2 is virtual, inverted, and further magnified.

Working Principle:
- The objective lens forms a magnified real image of the object.
- This image acts as an object for the eyepiece, which further magnifies it to produce a virtual image.
- The compound microscope allows observation of very small details of objects with high magnification.

Summary:
- Magnification depends on the focal lengths of the objective and eyepiece:
M_total = M_objective × M_eyepiece
- Produces a virtual, inverted, and highly magnified image of small objects.