Question

the earth is moving towards a stationary star with a velocity of 100km/s.if the wavelength of the light emitted by the star is 5000Å,then the change in wavelength apparent to an observer will be​

Answer 1

Question  :-

The earth is moving towards a stationary star with a velocity of 100 km/s.if the wavelength of the light emitted by the star is 5000 Å, then the change in wavelength apparent to an observer will be​

SoluTion :-

According to the Doppler effect in light,

$\sf {\Delta \lambda=\frac{v \lambda}{c} }$

$\sf {Then,}$

$\sf {\frac{10^{5}\times 5000\ \r{A}}{3 \times 10^{8} } }\\\\\\\sf {\Rightarrow 1.67\ \r{A}}$

Explanation :-

Light waves from a moving source experience the Doppler effect to result in either a red shift or blue shift in the light's frequency. The major difference is that light waves do not require a medium for travel, so the classical application of the Doppler effect doesn't apply precisely to this situation.