Question

A light source approaches the observer with velocity 0.8C. The Doppler shift of or light of the wavelength $5500\stackrel{0}{A}$ is:

• A. $4400\stackrel{0}{A}$
• B. $1833\stackrel{0}{A}$
• C. $3167\stackrel{0}{A}$
• D. $7333\stackrel{0}{A}$

Answer 1

The correct option is C $3167\stackrel{0}{A}$

According to Doppler's Principle

$\lambda =\lambda \sqrt{\frac{1-V/C}{1+V/C}}$ for $V=C$

$\lambda =5500\sqrt{\frac{1-0.8}{1+0.8}}=1833.3\therefore Shift=55001833.3=3167AA$