Question

Who invented the first compound microscope?
(a) Robert Hook
(b) Robert Koch
(c) Leeuwenhoek
(d) Z. Janssen

Answer 1

Hint: First compound microscope was discovered by the father and son. Being a teenage boy his father Hans helps him in creating the first microscope and in his writing. The compound microscope discovered by them has two lenses positioned close to the object and other as the eyepiece.

Complete step by step answer:
Z. Janssen was a spectacle maker while experimenting with several lenses placed at different distances in a tube, discovered that objects which were close to the lens farthest from the eye in the system of tubes appeared greatly enlarged. This system developed by him is modern-day used in microscopes and telescopes.
- Anton van Leeuwenhoek, very well known as the father of microscopy was a cloth merchant but ground his lense by himself to achieve superior quality lenses since his work required him to observe the thread structure of the cloth to determine its quality.
- Anton van Leeuwenhoek polished tiny lenses which had very high curvature. These lenses gave magnifications up to 270x. This was the highest magnification achieved during the sixteenth century.
- Leeuwenhoek was the first person to ever see and later describe bacteria, yeast in a drop of water, and the circulation of blood corpuscles in capillaries. He studied non- living and living organisms and reported his findings to the Royal Society of England and the French Academy. - Robert Hooke, also the English father of microscopy, re- confirmed Leeuwenhoek's discoveries of the tiny living organisms which are now known as microorganisms in a drop of water.
- Based on Leeuwenhoek's light microscope Hooke created his own microscope and then improved upon his design.
- Robert Koch is one of the founders and pioneers of modern bacteriology, his work includes identification of the specific causative agents of tuberculosis, cholera, and anthrax.
- Robert Koch gave experimental proofs for the theory of infectious disease, which included experiments on humans and animals.
So, the correct answer is, ‘(d) Z. Janssen.’

Note:
- Middelburg musume in Europe has the earliest microscope made by Jasnssen in 1595.
- Janssen microscope had three sliding tubes for different lenses which were able to magnify three to nine times the true size of the image.
- Galileo Galilei improved the microscope design in 1609 and named the device an occhiolino or little eye.