We wish to see inside an atom. Assuming the atom to have a diameter of 100 pm , this means that one must be able to resolve a width of say 10 pm . If an electron microscope is used, the minimum electron energy required is about

Step-by-step solution

In electron microscope, electrons are used as the 'light source'. The resolving power of a microscope is approximately equal to that of wavelength of the light used. The de Broglie wavelength of a particle is related to its momentum p by = h p = h m v The speed of required electron is v= h m = 6.63 10⁻³⁴ JS 9.11 10⁻³¹ ~kg 10⁻¹¹ ~m =7.28 10^7 ~m / s This corresponds to kinetic energy of E= 1 2 m v^2 aligned & = 1 2 9.11 10⁻³¹ (7.28 10^7 )^2 1 eV 1.6 10⁻¹⁹ ~J & =15.1 keV . aligned