The Doppler effect or Doppler shift is the change in frequency or wavelength of a wave in relation to an observer who is moving relative to the wave source.
Van Ki Asha means Hope of forest. Banas river of Rajasthan is known as Van Ki Asha. It passes through Udaipur originating from aravallis. It is the longest river with length 512 kms in Rajasthan having full flow.