Certain elements emit light of a specific wavelength when they are burned.
Historically, chemists used such emission wavelengths to determine whether
specific elements were present in a sample. Characteristic wavelengths for
some of the elements are given in the following table:
\(\begin{array}{llll}\mathrm{Ag} & 328.1 \mathrm{nm} & \mathrm{Fe} & 372.0
\mathrm{nm} \\ \mathrm{Au} & 267.6 \mathrm{nm} & \mathrm{K} & 404.7
\mathrm{nm} \\ \mathrm{Ba} & 455.4 \mathrm{nm} & \mathrm{Mg} & 285.2
\mathrm{nm} \\ \mathrm{Ca} & 422.7 \mathrm{nm} & \mathrm{Na} & 589.6
\mathrm{nm} \\ \mathrm{Cu} & 324.8 \mathrm{nm} & \mathrm{Ni} & 341.5
\mathrm{nm}\end{array}\) (a) Determine which elements emit radiation in the
visible part of the spectrum.
(b) Which element emits photons of highest energy? Of lowest energy? (c) When
burned, a sample of an unknown substance is found to emit light of frequency
\(6.59 \times 10^{14} \mathrm{~s}^{-1} .\) Which of these elements is probably
in the sample?