The redshift of the quasar Cygnus A is about 0.046. In the spectrum of this quasar what is the wavelength of the H_α line in the hydrogen spectrum (in nanometers)? The rest wavelength of the H_α line is 656.3 nanometers.

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Quizplus · Accepted Answer

The wavelength of the Hα line when observed from a quasar with a redshift of 0.046 can be calculated using the formula for redshift: λ_observed = λ_emitted * (1 + z), where λ_emitted is the rest wavelength of the Hα line (656.3 nm) and z is the redshift (0.046). Thus, λ_observed = 656.3 * (1 + 0.046) = 686.5 nm.

The Redshift of the Quasar Cygnus a Is About 0