Question

An echo is heard after 1.5s. What is the distance of the reflecting surface from the source given that the speed of sound is 346 m/s.

Answer 1

Given:

• An echo is heard = 1.5 s

• Speed of sound = 346 m/s

To be calculated:

Calculate the distance of the reflecting surface from the source.

Formula used:

Speed = Distance travelled / Time taken

Solution:

Time taken by sound to travel from source to the reflecting surface will be half of this time, which is

⇒ 1/2 × 1.5

⇒ 1.5/2

⇒ 0.75 seconds

Now,

Speed = Distance travelled / Time taken

★Substituting the values in the above formula,we get

⇒ 346 = Distance travelled / 0.75

⇒ Distance travelled = 346 × 0.75

⇒ Distance travelled = 346 × 75/100

⇒ Distance travelled = 25,950 / 100

⇒ Distance travelled = 259.5 m

Thus, the distance is 259.5 meters from the source.

Answer 2

Answer: 259.5 metres

Explanation:

Formula:

2S = V/Time

S = ? (distance)

V = 346 m/s (speed)

Time taken would be half to travel to reflecting surface would be half.

So T = 1/2 × 1.5 seconds

T = 0.75 s (time)

.°. S = 346 × 0.75

=> S = 346 × 3/4

=> S = 259.5 metres

Thus,

the distance of the reflecting surface from the source given that the speed of sound is 346 m/s is 259.5 metres