Question 15: NCERT Solutions for 12th Class Physics: Chapter 10-Wave Optics
For sound waves, the Doppler formula for frequency shift differs slightly between the two situations :
(i) source at rest; observer moving, and
(ii) source moving; observer at rest.
The exact Doppler formulas for the case of light waves in vacuum are, however, strictly identical for these situations. Explain why this should be so. Would you expect the formulas to be strictly identical for the two situations in case of light travelling in a medium?