Answer:
3 s.
Explanation:
Echo is defined as the repetition of a sound produced by the reflection of sound waves from an obstructing surface like a wall, mountain etc.
v = f*lambda
Where,
Lambda = wavelength of the wave
f = frequency of the wave = 1/t
v = velocity of the wave.
Distance there and back = initial ditance * 2
= 525 x 2
= 1050.
Time taken, t = lamda/velocity
= 1050 / 350
= 3 s.
So the delay is 3 seconds.
