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 990m, respectively is
`(t_(A))/(t_(B)) = ((d_(A))/(v))/((d_(B))/(v)) rArr (d_(A))/(d_(B)) = (660)/(330) = (2)/(3) = 2 :3`