Question

light and matter begin date: 9/2/2025 12:01:00 am due date: 9/5/2025 11:59:00 pm end date: 9/8/2025 11:59:00 pm problem 35: (3% of assignment value) the larger spectrum at the top of the figure shown illustrates an absorption spectrum from a source that is stationary with respect to the observer (you). the black lines are the absorption lines in the spectrum, at specific wavelengths. suppose instead that the source was actually moving toward you at a high speed. which of the (smaller) lettered spectra would you expect the observed spectrum to resemble? (in this scenario, the large spectrum at the top is the emitted spectrum.) hints: 0% deduction per hint. hints remaining: 1 feedback: 0% deduction per feedback.

Explanation:

Step1: Recall Doppler - effect concept

When a source moves towards an observer, there is a blueshift. The wavelengths of the spectral lines decrease.

Step2: Analyze the options

The black absorption lines will shift towards the shorter - wavelength (left - hand) side of the spectrum. In the given options, the lines in option B are shifted towards the left compared to the original spectrum, indicating a decrease in wavelength.

Answer:

B.