Question

A star is receding away from earth with a velocity of 10${}^{5}m/s$. If the wavelength of its spectral line is 5700 $\stackrel{o}{A}$, then Doppler shift will be

• A. 200 $\stackrel{o}{A}$
• B. 1.9 $\stackrel{o}{A}$
• C. 20 $\stackrel{o}{A}$
• D. 0.2 $\stackrel{o}{A}$

Answer 1

The correct option is B 1.9 $\stackrel{o}{A}$

$△\lambda =\frac{\nu }{c}\times \lambda =\frac{{10}^5}{3\times {10}^8}\times 5700=1.9\stackrel{o}{A}$