Chapter 10, Problem 10STP

To determine

The time taken by fish which is 15 m under water to make a round trip of the water.

Answer to Problem 10STP

Thetime taken is $\boxed{t=0.02\text{ s}}$ .

Explanation of Solution

Given:

The speed of sound in water is 1500 m/s and the distance of the sound travelled is 15m.

Formula used:

The expression for time, speed and distance is,

  $v=\frac{d}{t}$…… (1)

Here, v is the speed of sound, d is the distance travelled by the sound and t is the time taken.

Since for an echo to be recorded it has to travel to the object and back to the source and is given as d =2× d

Calculation:

Substituting 1500 m/s second in v and 2×15m in d in equation (1),

  $\begin{array}{l}1500=\frac{2\times 15}{t}\\ \boxed{t=0.02\text{ s}}\end{array}$

Conclusion:

Hence, the time taken is $\boxed{t=0.02\text{ s}}$ .