Assertion. Fine structure of the objects can be observed by transmission electron microscope (TEM).
Reason. Study of living cells cannot be done through TEM, because of high voltage, which is required to operate it, Kills the cells.

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

Assertion (A) : Majority of cells cannot be seen directly with naked eye because. Reason (R) : Cells are microscopic.

To study the living cells without staining, which of the following microscopes can be used?

To study the living cells without staining, which of the following microscopes can be used?

Which of the following statements are correct for the transmission electron microscope? I. Electron beam passess through the speciment and an electromagnetic objective lens which magnifies the image. II. A single electron beam is used throughout for the production of a magnifying image. III. This microscope is especially useful in studying the surface structures of intact cells and viruses. IV. A living intact specimen can be used for viewing.

Read the following text and answer the following questions on the basis of the same: Electron Microscope Electron microscopes use electrons to illuminate a sample. In Transmission Electron Microscopy (TEM), electrons pass through the sample and illuminate film or a digital camera. Resolution in microscopy is limited to about half of the wavelength of the illumination source used to image the sample. Using visible light the best resolution that can be achieved by microscopes is about -200nm . Louis de Broglie showed that every particle or matter propagates like a wave. The wavelength of propagating electrons at a given accelerating voltage can be determined by l= (h)/(sqrt(2m_(e )v)) . Thus the wavelength of electrons is calculated to be 3.88pm when the microscope is operated at 100keV, 2.74pm at 200keV and 2.24pm at 300keV. However, because the velocities of electrons in an electron microscope reach about 70% the speed of light with an accelerating voltage of 200keV, there are relativistic effects on these electrons. Due to this effect, the wavelength at 100keV, 200keV and 300keV in electron microscopes is 3.70pm, 2.51 pm and 1.96pm, respectively. Anyhow, the wavelength of electrons is much smaller than that of photons (2.5pm at 200keV). Thus if electron wave is used to illuminate the sample, the resolution of an electron microscope theoretically becomes unlimited. Practically, the resolution is limited to ~-0.1 nm due to the objective lens system in electron microscopes. Thus, electron microscopy can resolve subcellular structures that could not be visualized using standard fluorescences microscopy. As the accelerating voltage increases, the wavelength of electron as wave

Read the following text and answer the following questions on the basis of the same: Electron Microscope Electron microscopes use electrons to illuminate a sample. In Transmission Electron Microscopy (TEM), electrons pass through the sample and illuminate film or a digital camera. Resolution in microscopy is limited to about half of the wavelength of the illumination source used to image the sample. Using visible light the best resolution that can be achieved by microscopes is about -200nm . Louis de Broglie showed that every particle or matter propagates like a wave. The wavelength of propagating electrons at a given accelerating voltage can be determined by l= (h)/(sqrt(2m_(e )v)) . Thus the wavelength of electrons is calculated to be 3.88pm when the microscope is operated at 100keV, 2.74pm at 200keV and 2.24pm at 300keV. However, because the velocities of electrons in an electron microscope reach about 70% the speed of light with an accelerating voltage of 200keV, there are relativistic effects on these electrons. Due to this effect, the wavelength at 100keV, 200keV and 300keV in electron microscopes is 3.70pm, 2.51 pm and 1.96pm, respectively. Anyhow, the wavelength of electrons is much smaller than that of photons (2.5pm at 200keV). Thus if electron wave is used to illuminate the sample, the resolution of an electron microscope theoretically becomes unlimited. Practically, the resolution is limited to ~-0.1 nm due to the objective lens system in electron microscopes. Thus, electron microscopy can resolve subcellular structures that could not be visualized using standard fluorescences microscopy. In electorn microscope, electron is used