QUIZ BYPNKThe minimum distance require to hear an echo, it the speed of sound in air is 350mst and perception of() 17(の 35(c) 17.52 The speed of a sound wave whose frequency is 200 Hz in ar (medium-I) is 360ms1t is3 A sound wave travelling in positive X-direction reflects from a rigid surface, then its(a) frequency changes(c) wavelength changes(b) speed changes(d none of theseDirections for question no. 4 to 6Oscillations of a pendulum bob are periodic in nature. By considering the above facquestions. (Take 9, = 10 msカt answer the following4 Number of oscillations completed in unit time is(b) 12(o) 2(c) 114ir t,-10, then the length of the pendulum is(a) 15,m(b) 2(d) of theseoray aun!. then the time"it s taken to a celestial body, whose acceleration due to gravity is 규 aat, then the time taken tocomplete one oscillation(a) increases by 'n times6(b) decreases by 'n' times(d we cannot predictFIITJEE