The highest achievable resolving power of a microscope is limited only by the wavelength used; that is, the smallest item that can be distinguished has dimensions about equal to the wavelength. Suppose one wishes to "see" inside an atom. Assuming the atom to have a diameter of 200 pm, this means that one must be able to resolve a width of, say, 20 pm. (a) If an electron microscope is used, what minimum electron energy is required? (b) If a light microscope is used, what minimum photon energy is required? (c) Which microscope seems more practical and why? (a) Number n Units v (b) Number n Units v I-\\ A particle of mass 4.77 x 10'27 kg has a potential energy of 6.08 x 10'15 J, independently of its position. If its energy is 9.80 x 10'15 J, what is its angular wave number? Number n Units v You will nd in Chapter 39 that electrons cannot move in denite orbits within atoms, like the planets in our solar system. To see why, let us try to "observe" such an orbiting electron by using a light microscope to measure the electron's presumed orbital position with a precision of, say, 30 pm (a typical atom has a radius of about 100 pm). The wavelength of the light used in the microscope must then be about 30 pm. (a) What would be the photon energy of this light? Number Units v (b) How much energy would such a photon impart to an electron in a headon collision? Number Units v