The Total solution for NCERT class 6-12
The 6563 Å line emitted by hydrogen ina star is found to be red shifted by 15 Å. Estimate the speed with which thestar is receding from the Earth.
Wavelength of line emitted by hydrogen,
λ = 6563 Å
= 6563 ×10−10 m.
Star’sred-shift,
Speed of light,
Let thevelocity of the star receding away from the Earth be v.
The redshift is related with velocity as:
Therefore, the speed with whichthe star is receding away from the Earth is 6.87 × 105 m/s.