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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
Detailed Solution
The resolving power of a microscope is its ability to show two close points as separate; it improves as the wavelength of the radiation used becomes shorter.
A light microscope uses visible light and can resolve points about 0.2 micrometre (200 nm) apart.
An electron microscope uses a beam of electrons, whose wavelength is much shorter than that of visible light, so it can resolve points only about 0.1 to 0.2 nm apart.
Its resolution is therefore much higher than that of the light microscope, which made it possible to see the fine structure (ultrastructure) of the cell and its organelles.
The statement giving 200-350 nm for the electron microscope has the two values interchanged.
Electrons have very poor penetrating power, so the electron microscope needs ultra-thin sections, and the wavelength of electrons is shorter, not longer, than that of light.
So the breakthrough came because the resolution power of the electron microscope is much higher than that of the light microscope.
A light microscope uses visible light and can resolve points about 0.2 micrometre (200 nm) apart.
An electron microscope uses a beam of electrons, whose wavelength is much shorter than that of visible light, so it can resolve points only about 0.1 to 0.2 nm apart.
Its resolution is therefore much higher than that of the light microscope, which made it possible to see the fine structure (ultrastructure) of the cell and its organelles.
The statement giving 200-350 nm for the electron microscope has the two values interchanged.
Electrons have very poor penetrating power, so the electron microscope needs ultra-thin sections, and the wavelength of electrons is shorter, not longer, than that of light.
So the breakthrough came because the resolution power of the electron microscope is much higher than that of the light microscope.