In which scenario will a woman observe a continuous rainbow of colors interrupted by a few dark absorption lines in the spectrum?

• A. When she observes the emission spectrum of a heated gas directly
• B. When she views the spectrum of a pure incandescent solid
• C. When she looks at sunlight reflected off a white surface
• D. When sunlight passes through a cool gas before reaching her eyes

Answer: (D)

Verified step by step guidance

1. Understand the nature of different types of spectra: emission spectra show bright lines on a dark background, absorption spectra show dark lines on a continuous bright background, and continuous spectra show an unbroken range of colors without lines.
2. Recall that a pure incandescent solid (like a heated filament) produces a continuous spectrum, which is a smooth gradient of colors without interruptions.
3. Recognize that when sunlight (which is a continuous spectrum) passes through a cooler gas, atoms in the gas absorb specific wavelengths of light, causing dark absorption lines to appear in the continuous spectrum.
4. Identify that observing sunlight reflected off a white surface generally shows a continuous spectrum without absorption lines because the light has not passed through a cool gas.
5. Conclude that the scenario where a woman observes a continuous rainbow of colors interrupted by dark absorption lines is when sunlight passes through a cool gas before reaching her eyes, producing an absorption spectrum.