A hydrogen line in a star’s spectrum has a frequency of 6.17×10^14 Hz when stationary. In Rigel’s spectrum, it is shifted

Question

A hydrogen line in a star’s spectrum
has a frequency of 6.17×10^14 Hz
when stationary. In Rigel’s spectrum,
it is shifted downward by 4.26×10^10
Hz. What is Rigel’s velocity relative
to us?
PLS HELP!

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Thiên Di 3 years 2021-08-28T13:07:14+00:00 1 Answers 30 views 0

Answers ( )

    0
    2021-08-28T13:08:18+00:00

    Answer: V = 4.35 × 10^12 m/s

    Explanation: To calculate Rigel velocity relative to us, we should use doppler effect formula.

    Fo = (c ) / ( c – Vs) × f

    Fo/f = (c ) / ( c – Vs)

    4.26 × 10^10 = (3×10^8) 6.17×10^14/(3×10^8 – V)

    4.26×10^10/6.17×10^14 = (3×10^8)/(3×10^8 – V)

    6.9×10^-5 = (3×10^8)/(3×10^8 – V)

    Cross multiply

    20713.13 – 6.9×10^-5V = 3×10^8

    Collect the like terms

    6.9×10^-5V = 3×10^8 – 20713.13

    6.9×10^-5V = 299979286.9

    V = 299979286.9/6.9×10^-5

    V = 4.3475 × 10^12 m/s

    Therefore, Rigel’s velocity relative to us is 4.3475 × 10^12 m/s

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