Subject :NSO Class : Class 9
A man standing in front of a large wall claps at a regular frequency of 10 Hz. He finds that the echoes coincide with his clapping. (The speed of sound in air is 330 m s-1.)
(i) Time taken between successive clapping is 0.1 s.
(ii) The distance between the man and the wall, after he stops clapping, if he hears one more echo is 33 m.
(iii) The distance between the man and the wall, after he stops clapping, if he hears four more echoes is 66 m.
A Only (i) and (ii) are correct.
B Only (ii) and (iii) are correct.
C Only (i) and (iii) are correct.
D All (i), (ii) and (iii) are correct.