(a) what velocity must a helium atom (6.647 x 10^27 kg) have, to be diffracted by a film of silver atoms in which the spacing between atoms is 1.00 x 10-10 m?
(i) what is the wavelength requirement for radiation or an object (with resting mass) to undergo optimum diffraction around an (or between) object(s) ?
(ii) what relationship will you use to determine the velocity of helium traveling as a wave?
(b) electrons accelerated by a certain potential are diffracted by a thin film of gold. a beam of protons accelerated through the same potential are not diffracted by that same thin film of gold. briefly explain why this is so.