Chapter 40 - All About Atoms - Problems - Page 1251: 74

$\hbar = 1.06\times 10^{-34}~J\cdot s = 6.59\times 10^{-16}~eV \cdot s$

$\hbar = \frac{h}{2\pi}$ $\hbar = \frac{6.626\times 10^{-34}~J\cdot s}{2\pi}$ $\hbar = 1.06\times 10^{-34}~J\cdot s$ $\hbar = (1.06\times 10^{-34}~J\cdot s)(\frac{1~eV}{1.6\times 10^{-19}~J})$ $\hbar = 6.59\times 10^{-16}~eV\cdot s$