The hydrogen Balmer line H _$\beta$ has a wavelength of 486.1 nm in the laboratory. It is observed in a quasar at 2430.5 nm. What is the fractional change in wavelength or redshift z of this quasar? A) 5 B) 0.5 C) 0.25 D) 4 E) 1944.4

Question

Quizplus · Accepted Answer

Using the formula for redshift, $\frac{\Delta\lambda}{\lambda} = z$, we can determine the redshift of the quasar: $$z = \frac{2430.5~\mathrm{nm} - 486.1~\mathrm{nm}}{486.1~\mathrm{nm}} = 4$$ Therefore, the fractional change in wavelength or redshift z of this quasar is 4. Choice D is the correct answer.

The Hydrogen Balmer Line H β\betaβ Has a Wavelength of 486

The Hydrogen Balmer Line H _$\beta$ Has a Wavelength of 486