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?

Question

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.

Arora · Answer

Use the same formula I mentioned in the question on a moving star. In that formula, 'v' is considered positive when the object is moving away, and negative when moving closer.

Jake · Answer

It is hotter than the sun