If source and observer are moving towards each other with same speed and aftercrossing they are
receding each other then frequency observed by observer:
A sonar depth finder in a boat uses sound signals to determine the depth of water. Fourseconds after the sound leaves the boat it returns to the boat because of reflection fromthe bottom. Assume the speed of sound in water is 1,460 meters per second. The depth of the water is, in meters, :
The spectrum of a star’s light is measured and the wavelength of one of the lines as thesodium’s line is found
to be 589 nm. The same line has the wavelength of 497 nm whenobserved in the laboratory. This means the
star is
A whistle is revolved with high speed in a horizontal circle of radius R. to an observer at the centre of the circle the frequency of the whistle will appear to be:
