question_answer 29)

                  Sound waves of wavelength \[\lambda \] travelling in a medium with a speed of \[\upsilon \] m/s enter into another medium where its speed is 2u m/s. Wavelength of sound waves in the second medium is                 (a) \[\lambda \]                                    (b) \[\frac{\lambda }{2}\]                 (c) \[2\lambda \]                                   (d) \[4\lambda \]

Answer:

                  (c) \[\upsilon =\,v\lambda \]                 \[2\upsilon =\,v\lambda '\]                 \[\therefore \]\[\lambda '\,=2\lambda \]