Question

Resolution power of transmission electron microscope is of the sub nanometer level. This is because:

• A. the focal length of the electron microscope is significantly larger.
• B. the contrast is enhanced by staining with atoms of heavy metal.
• C. electron beams have much shorter wavelengths than visible light.
• D. the electron microscope has a much greater ratio of image size to real size.

Hint:

Resolution $\propto$ 1 Wavelength. Shorter waves = Better detail.

Answer 1

The Correct Option is C

Step 1: Concept
The resolution of a microscope is limited by the wavelength of the radiation used to image the specimen.

Step 2: Meaning
According to Abbe's equation, smaller wavelengths allow for a smaller limit of resolution and thus higher resolving power.

Step 3: Analysis
Visible light has wavelengths between 400-700 nm. In contrast, high-velocity electrons behave as waves with wavelengths thousands of times shorter than photons. This allows the Transmission Electron Microscope (TEM) to resolve structures that are far too small to be seen with a light microscope.

Step 4: Conclusion
The superior resolution of TEM is directly due to the extremely short de Broglie wavelength of electrons. Final Answer: (C)