Question

A major breakthrough in the studies of cells came with the development of electron microscope. This is because __________.

• A. The resolution power of the electron microscope is much higher than that of the light microscope
• B. The resolving power of the electron microscope is 200-350 nm as compared to 0.1-0.2 nm for the light microscope
• C. Electron beam can pass through thick materials, whereas light microscopy requires thin sections
• D. The electron microscope is more powerful than the light microscope as it uses a beam of electrons which has wavelength much longer than that of photons

Answer 1

The correct option is A The resolution power of the electron microscope is much higher than that of the light microscope

This is the correct answer since Resolution of the electron microscope (EM) is inversely proportional to the wavelength of the beam. While visible light has a wavelength between 400nm to 700nm, an electron beam in the EM has a wavelength of about 2.5pm (picometre). This is much lower than the wavelength of visible light and hence it results in much higher Resolution. Although this option uses the term "Resolution power" there exists no such thing, and they probably mean resolution.
Resolving power is the ability to distinguish between two closely spaced points. Since EM is much more powerful than light microscope (LM), it is unlikely that EM would have a resolving power much higher than the LM. Also, the resolving power of the LM is about 0.1 - 0.2μm and not nm.
Electron beams cannot travel through thick materials.
The electron beam has much lower wavelength than the photon beam.