In the laboratory,an atom emits a spectral line at a wavelength of 400 nanometers.In the spectrum of a star,the same spectral line is found to have a wavelength of 410 nanometers.What can be said about the star?
A)It is hotter than the Sun
B)It is moving toward the Earth
C)It is moving away from the Earth
D)It contains elements that are not found on Earth

Question

Quizplus · Accepted Answer

The difference in the wavelength of the spectral line between the laboratory and the star is 10 nanometers, which corresponds to a Doppler shift indicating that the star is moving away from the observer. This is known as a redshift, and it is a common way to measure the velocity of stars and galaxies. The other answer choices are not supported by the given information.

In the Laboratory,an Atom Emits a Spectral Line at a Wavelength