Question

A star producing light of wavelength 6000 Å moves away from the earth with a speed of 5 km/sec. Due to Doppler effect the shift in wavelength will be $(c = 3 \times 10^{8}m/\sec)$.

• A. 0.1 Å
• B. 0.05 Å
• C. 0.2 Å
• D. 1 Å

Answer 1

Answer: (A)

0.1 Å

Answer 2

Doppler’s shift is given by

$\Delta\lambda = \frac{v\lambda}{c} = \frac{5000 \times 6000}{3 \times 10^{8}} = 0.1Å$