Passage I
Study 1

Using infra-red imaging in a laboratory
setting, scientists measured the reflectance (the
percent of light that is reflected by a surface) of
each of 3 isotopes (chemical forms) of carbon
(carbon-12, carbon-13, and carbon-14) and of a
carbon compound (Cyanide).Reflectance was
measured, in each case, at light wavelengths
between 500 and 800 nanometers (nm). Figure 1
shows the data for the 3 carbon isotopes and
Cyanide.
At the wavelengths included in Study 1, as the
wavelength of light increases, the reflectance of
Cyanide: