Question

A star is moving away from the earth's surface with the speed of ${10}^{6}m/s$. If the wavelength of spectral lines received from the stars is $5700\mathring{A}$. The Doppler's shift will be

• A. $200\mathring{A}$
• B. $19\mathring{A}$
• C. $20\mathring{A}$
• D. $0.2\mathring{A}$

Answer 1

The correct option is B $19\mathring{A}$

The correct answer is option(B).

Doppler's shift is given by,

$\Delta \lambda =\frac{v\lambda }{c}=\frac{{10}^6\times 5700}{3\times {10}^8}=19\AA$