Question

An object is 11 km below sea level. A research
vessel sends down a sonar signal to confirm
this depth. After how long can it expect to get
the echo? (Take the speed of sound in sea water
as 1,520 m s-1.)
6) 14.47 s
(a) 15.30 s
(c) 12.20 s
(d) 11.13 S

Answer 1

Given that,

An object is 11 km below sea level.

The speed of sound in sea water is 1520 m/s

To find,

After how long can it expect to get  the echo?

Solution,

The total distance covered by the sonar beam is given by :

d = 2 × 11

d = 22 km

Let t is the time after which it is expect to get the echo. So,

$t=\dfrac{d}{v}\\\\t=\dfrac{22000}{1520}\\\\t=14.47\ s$

So, the correct option is (a) i.e. 14.47 seconds.