If the two tubes of lengths 50cm and 51cm closed at one end produce 7 beats in two second, when sounded to their fundamental notes neglecting end correction , then velocity of sound in air will be

Options

A. 350m/s
B. 352m/s
C. 354m/s
D. 357m/s

Answer

D

Explanation

As `L_2 gt l_1 " " therefore n_1 gt n_2`
`(v)/(4l_1) - (v)/(4l_2) = 3.5 therefore n_1-n_2 =3.5`
`therefore 3.5 = v[(1)/(4xx0.50)-(1)/(4xx0.51)]`
`=v[1/2-(1)/(2.04)]`
`=v[(2.04-2)/(2.04xx2)]`
`therefore v[0.04] = 3.5xx2.04xx2`
`v=(3.5xx2.04xx2)/(0.04) = 357 m//s`