A light source approaches the observer with velocity 0.5 cm. Doppler shift for light of wavelength 550 Å is

616 Å 1833 Å 5500 Å 6160 Å

1833 Å

In case of light, $v'=\frac{c+v}{c}.v$ and $\frac{v'}{v}=\frac{c+v}{c}=\frac{λ}{λ'}$ or $λ'=\frac{λc}{c+v}=\frac{5500xc}{c+0.5c}=\frac{5500x2}{3}=3667Å$ $∴Δλ= (5500 −3667)Å =1833Å$