Answer:
Explanation:
Given Data:
rest wavelength = λ₀=121.6nm
Star A wavelength = λa=120.5nm
Star B wavelength = λb=121.2nm
Star C wavelength = λc=121.9nm
Star D wavelength = λd=122.9nm
According to Doppler shift formula,
we have
v/c=(λ-λ₀)/λ₀
As we know c=speed of light=3*10^8m/s⁻¹
a.
Star A: v=(120.5-121.6)(3*10^8)/121.6 = -2.71*10^6m/s(towards)
Star B: v=(121.2-121.6)(3*10^8)/121.6 = -9.87*10^5m/s(towards)
Star C: v=(121.9-121.6)(3*10^8)/121.6 = 7.40*10^5m/s(away)
Star D: v=(122.9-121.6)(3*10^8)/121.6 = 3.21*10^6m/s(away)
b.
Star D is moving fastest relative to us.