A major breakthrough in the studies of cells came with the development of electron microscope. This is because
- Electron beam can pass through thick materials, whereas light microscopy requires thin sections
- The resolution power of the electron microscope is much higher than that of the light microscope
- 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
- The resolving power of the electron microscope is 200-350 nm as compared to 0.1-0.2 nm for the light microscope
Answer
(2) The resolution power of the electron microscope is much higher than that of the light microscope
Solution
The resolving power of a microscope depends on the wavelength used: the shorter the wavelength, the finer the detail that can be resolved.
∵ A beam of electrons has a wavelength much shorter than that of visible light, the electron microscope resolves about 0.1–0.2 nm, whereas the light microscope resolves only about 200 nm.
⇒ The resolution power of the electron microscope is much higher, so ultrastructure of cell organelles could be studied for the first time.
Statement (1) is wrong (electron microscopy needs ultrathin sections), statement (3) is wrong (the wavelength of electrons is much shorter, not longer) and statement (4) interchanges the two values.
Answer: (2)