A sonar device fixed to the ship is used to find the depth of the ocean. The ultrasonic sound produced gets reflected from the ocean bed and the time taken for the reflected sound to reach the sonar is 4 s, then write the following steps in sequence to find the depth of the ocean bed (d). (Speed of sound in ocean water is 1500 m `s^(-1)`)
(A) Use the formula, speed = `("distance travelled by the sound (2d)")/("Total time taken (t)")`
(B ) The distance travelled by the sound is equal to twice the depth of the ocean bed (d).
(C )Note the total time (1) taken by the reflected sound to reach the sonar from ocean bed from given data.
(D ) Substitute the values in the given formula, and find the value of 'd'.

Options

A. a b c d
B. b a c d
C. d a c b
D. c b a d

Answer

D

Explanation

From the given data, collect the total time taken, 1 = 4 s. The distance travelled by sound` = 2 xx` (depth of the ocean bed).
speed `=(2d)/( t ) to a`
` d= (1500 xx t)/( 2 ) = (1500 xx 4 )/( 2 ) = 3000 m = 3km`
So, the depth of the ocean bed, (d) = 3 km.