The answer of the above question is
1. Velocity is 330m/s
2.Distance between two walls is 1650m
But i want to know how this answer came??
Answers
Correct question:
- Sunil is standing between two walls the wall closest to him is at a distance of 660m if he shouts he hears the first echo after 4s and another after another 2 seconds.
Find
i) Velocity of sound in Air ?
ii) Distance between two walls
(As this question is from State board; And, It by printing mistake in some books, The distance is given as 360 meters; And answer is also given there as 330 and 1650 respectively; So, if we solve this problem by considering distance 360 meters, then answer will get wrong).
Answer:
Velocity = 330m/s
Distance between two walls = 1650 meters
Given information:
Suppose sunil is standing is a room between 2 walls.
Wall closest to sunil is at distance of 660 meters.
And, If he shouts, then he heard the Echo from his nearest wall in 4 seconds.
And, Another wall echo is heard in next 2 seconds.
To find: i) Velocity of sound in Air ?
ii) Distance between two walls
Explanation:
Method I :
i) Velocity of sound in Air:
Velocity = Distance / Time/2 (Because we heard sound after getting reflected back)
Velocity = 660 / 2
Velocity = 330 m/s
Therefore, Velocity of sound in Air is 330 m/s.
ii) What is the distance between two walls ?
For first wall,
Distance = ?
Velocity = 330 m/s
Time = 4 seconds
Distance = Velocity * time
Distance = 330 * 4
Distance = 1320 meters -------- (i)
For second wall,
Distance = ?
Time = 2 seconds
Velocity = 330 m/s
Distance = Velocity * 2/ time
Distance = 330 * 1
Distance = 330 meters ------- (ii)
Adding equation (i) and (ii),
Distance between 1st wall + Distance between 2nd wall = Distance between two walls
Distance between two walls = 1320 + 330
Distance between two walls = 1650 meters
Therefore, Distance between 2 walls is 1650 meters.
Method II :
i) Velocity of sound:
Velocity of sound = Distance/time
Velocity of sound = 660/2
Velocity of sound = 330 m/s
ii) Distance between two walls:
Distance = Velocity * total time
Distance = 330 * 6
Distance = 1650 meters