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 light =3×108 ms−1) [Main 2017]
a. 17.3 GHz
b. 15.3 GHz
c. 10.1 GHz
d. 12.1 GHz