Question

Some copper compounds emit green light when they are heated in a flame. How would you determine whether the light is of one wavelength or a mixture of two or more wavelengths?

Short answer

To determine if the green light emitted from the heated copper compound is of a single wavelength or a mixture of two or more wavelengths, a spectroscope or a spectrometer can be used. The analysis of the emission spectrum will reveal whether the light is monochromatic or polychromatic.

Step-by-step solution

Understanding the Basics

Start by reviewing the basics of light emission. When a copper compound is heated in a flame, the energy from the flame excites the electrons in the copper compound. These electrons then emit light when they return to a lower energy state. The color of the light corresponds to the particular energy difference of the electron transitions - in this case, green light.

Proposing the Method

To determine whether the green light emitted is of a single wavelength or it's composed of multiple wavelengths, use a device called a spectroscope or a spectrometer. These devices separate light into its component wavelengths, which then can be individually evaluated.

Evaluating the Emission Spectrum

With the spectroscope or spectrometer, analyze the emission spectrum of the light. If the green light emitted is monochromatic (of one wavelength) only one distinct line, corresponding to green color in the visible spectrum, will be observed. However, if the light is polychromatic (composed of multiple wavelengths), several discrete lines or bands within and possibly beyond the green region of the visible spectrum will be observed.