A train us moving with a velocity of 25 m/s and a car is moving behind it by a velocity of 8 m/s in same direction The relative velocity of train with respect to car is
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