The hydrogen Balmer H $\alpha$ line with laboratory wavelength 656.3 nm is identified in emission in the spectrum of a quasar at 1968.9 nm. What is its redshift?
A)z = 0.3
B)z = 1.0
C)z = 2.0
D)z = 3.0

Question

Quizplus · Accepted Answer

We can use the formula for redshift, z = (λ_observed - λ_emitted)/λ_emitted, where λ_observed is the measured wavelength and λ_emitted is the rest wavelength. From the given information, λ_observed = 1968.9 nm and λ_emitted = 656.3 nm. Plugging in these values, we get z = (1968.9 - 656.3)/656.3 = 2. Therefore, the best choice is C with a redshift of z = 2.0.

The Hydrogen Balmer H α\alphaα Line with Laboratory Wavelength 656

The Hydrogen Balmer H $\alpha$ Line with Laboratory Wavelength 656