Chapter 4, Problem 32P

Calculate the de Broglie wavelength of the following:

(a) electrons that have been accelerated to a kinetic energy of $1.20\times \text{1}{0}^7\text{J}{\text{mol}}^{-1}$

(b) a helium atom moving at a speed of ${\text{353 m s}}^{-\text{1}}$ (the root-mean-square speed of helium atoms at 20 K)

(c) a krypton atom moving at a speed of ${\text{299 m s}}^{-\text{1}}$ (the root-mean-square speed of krypton atoms at 300 K)