Two tuning forks A and B of frequencies 200 Hz and 400 Hz are vibrated simultaneously. Then, the ratio of time taken by the sound produced by A and B to travel 660 m and 990 m, respectively in air is ______ (velocity of the sound in air `= 330 m s^(-1)`)

Options

A. `1:2`
B. `1:3`
C. `2:3`
D. `1:1`

Answer

C

Explanation

Velocity of sound .v . `=("distance travelled by sound (d)")/("time taken (t)")`
Then, the ratio of time taken by A and B to cover a distance of 660 m and 990 m, respectively is
` (t_A)/(t_B) = ((d_A)/(v ))/((d_B)/((d_B)/(v)) implies (d_A)/(d_B) = (660 )/(990)=2/3 = 2:3`