A whistle producing sound waves of frequencies 9500Hz and above is approaching a stationary person with speed vms–1 . The velocity of sound in air is 300ms–1 . If the person can hear frequencies upto a maximum of 10000Hz, the maximum value of v upto which he can hear the whistle is
(a) 30ms–1
(b) 15√2ms-1
(c) 15/√2ms-1
(d) 15ms–1 .
