Question

Who invented electron microscope
A. Janssen
B. Edison
C. Knoll and Ruska
D. Landstiner

Answer 1

Hint: Electron microscope is a device through which high resolution images of the non biological and biological specimens are obtained. As a source of illumination, it utilizes a beam of accelerated electrons.

Complete Answer:
- The high resolution image obtained by the electron microscope can be magnified upto nanometer scale.
- For various biomedical research to examine the detailed structure of cells, tissues, organelles, and other macromolecular compounds they use electron microscopes.
- The first prototype of the electron microscope was invented by Ernst Ruska a physicist and the electrical engineer Max Knoll.
- It was efficient to magnify up to four hundred power magnifications and was the first apparatus to demonstrate principles of electron microscopy practically.

Therefore the correct answer is (C) Knoll and Ruksa.

Additional information:
- Zacharias Janssen: Janssen and Hans were the first men to give the concept of the compound microscope.
- Thomas. A. Edison: Edison along with William Dickson invented a device called kinetoscope. It is a device that exhibits early motion pictures. The images are viewed through a peephole at the top of the device.
- Karl Landsteiner: Landsteiner was well known for his contribution in the field of haematology. He was the first person to discover the ABO blood system. To visualize the spirochetes, he introduced dark field microscopy.

Note: The magnification of an electron microscope is more than 10,000 greater than that of a light microscope. Unlike optical microscopes, the colour information is not recorded in an electron microscope. The disadvantage of an electron microscope is that it is very expensive and huge. It is very sensitive to external magnetic fields and vibrations.