## Chemistry: The Central Science (13th Edition)

$2.998 \times 10^{13}s^{-1}$
*Strategy: using the formula $$\lambda\times\nu=c$$ in which $\lambda$ : wavelength of radiation $\nu$ : frequency of radiation $c$ : speed of light (we take the speed of light in vacuum, so $c \approx 2.998 \times 10^8m/s$) - Step 1: we know the radiation has a wavelength of $10\mu m$, so $\lambda = 10\mu m = 10^{-5}m$ (remember that $c$ and $\lambda$ must be in compatible units to do the calculation). - Step 2: Calculate frequency of radiation ($\nu$) $\nu = \frac{c}{\lambda} = \frac{2.998\times10^{8}m/s}{10^{-5}m} \approx 2.998\times10^{13} (s^{-1})$ That's the answer you need.