The H_γ line has a wavelength of 434.0 nm when observed in the laboratory. If the H_γ line appears in a stars spectrum at 434.5 nm, what is the radial velocity of the star? A) 346 km/s away from the observer B) 346 km/s toward the observer C) 1.3 × 10⁸ m/s away from the observer D) 1.3 × 10⁸ m/s toward the observer E) The radial velocity of the star cannot be determined from this information.

Question

Quizplus · Accepted Answer

The observed wavelength is longer than the laboratory wavelength, indicating a redshift. This means the star is moving away from the observer. The radial velocity can be calculated using the formula: v = c * (Δλ/λ₀), where Δλ = 434.5 nm - 434.0 nm = 0.5 nm, λ₀ = 434.0 nm, and c = 3 × 10⁵ km/s. This gives v ≈ 346 km/s away from the observer.

The H γ Line Has a Wavelength of 434

The H_γ Line Has a Wavelength of 434