Discussion Forum

An observer is moving with half the speed of light towards a stationary microwave source emitting waves at frequency 10 GHz . What is the frequency of the microwave measured by the observer ?  [ speed of ight = 3 x 10⁸ ms^-1 ]

Answer:

Explanation:

As the observer is moving towards the source, so frequency of waves emitted by the source will be given by the formula.

         $f_{observed}= f_{actual}.(\frac{1+\frac{v}{c}}{1-\frac{v}{c}})^{\frac{1}{2}}$

 Here, frequency     $\frac{v}{c}=\frac{1}{2}$

  So,           $f_{observed}= f_{actual} (\frac{3/2}{1/2})^{\frac{1}{2}}$

$\therefore$                $f_{observed}= 10\times\sqrt{3}=17.3GHz$