Because dark line spectra result from passing white light through ionized gasses and plasmas, which is what the atmosphere of stars are made of. These frequencies are scattered by the star's atmosphere as it leaves the surface (photosphere) of the star, and don't make it to earth.
Surface miners work aboveground. (Apex) ^-^
solution:
1.6 m/s = 96 m/min (in other words, 1.6 m/s x 60 s/min)
96 m/min x 8.3 min = 796.8 m

An ... (Base ) .... is a compound that turns red litmus paper blue and is often found in soaps and detergents.
Answer:
Explanation:
fringe separation or fringe width is directly proportional to wavelength .
Δ₁ / Δ₂ = wave length of first laser / wavelength of second laser
Δ₁ is fringe separation in first case and Δ₂ is fringe separation in second case.
putting the given values
632.8 / wavelength of second laser = 4.5 / 4.64
wavelength of second laser = 632.8 x (4.64 / 4.5)
= 652.48 nm
652 nm