A sound wave is produced fron a source ans an echo is heard t seconds afterwards. If d is the distance of the reflecting surface from the source, v the speed, p the wavelength and T the period of the wave, then
d = \(\frac{2t}{\lambda}\)
d = \(\frac{\lambda t}{2T}\)
d = \(\frac{2T}{\lambda t}\)
d = \(\frac{\lambda T}{2t}\)
Correct answer is B
V = \(\frac{2d}{t}\)
f\(\lambda = \frac{2d}{t} = \frac{\lambda}{T} = \frac{2d}{t}\)