Question

The wavelength of wave of 5000 Å coming
from a star at distance in experience
5200 Å, then what is the velocity?
A) 1.2 * 10^7 cm/s
B) 1.2 * 10^7 m/s
C) 1.2 * 10^7 km/s
D) 1.2 km/s
​

Answer 1

Answer:

$\bull \sf \: The \: velocity \: of \: star \: is \: 1.2 × 10^7m/s.$

Explanation:

$\sf \: \underline{Given \: that,}$

$\bull \sf Initial \: wavelength =5000Å \\ \\ </h3><p></p><h3>\bull \sf Final \: wavelength = 5200Å \\ \\ </h3><p></p><h3>\bull \sf Speed \: of \: light = 3 × 10^8 m/s</h3><h3>$

$\sf \underline{As \: we \: know \: that,</h3><h2>} \\ \\ \red\bigstar {\boxed {\sf{v = \frac{ Δ \lambda}{ \lambda} \: . \: c}}}$

$\sf[ Putting \: values ] \\ \\ \leadsto \: \sf v = \frac{ 5200Å - 5000Å }{5000Å}.3 \times 10 {}^{8} </h3><h3> \\ \\ \leadsto \sf \: v = \frac{200Å}{5000Å} .3 \times 10 {}^{8} \\ \\ \leadsto \sf \: v = 0.04 \times 3 \times 10 {}^{8} \\ \\ \leadsto \sf \: v = 1.2 \times 10 {}^{7} ms {}^{ - 1} \: \green \bigstar$