A person rings a metallic bell near a strong concrete wall. He hears the echo after 0. 3.s. If the sound moves with a speed of 340 m/s, how far is the wall from him?

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Q: 49 (CDS-I/2016)
A person rings a metallic bell near a strong concrete wall. He hears the echo after 0.
3.s. If the sound moves with a speed of 340 m/s, how far is the wall from him?

question_subject: 

Science

question_exam: 

CDS-I

stats: 

0,18,46,21,18,18,7

keywords: 

{'metallic bell': [0, 0, 0, 1], 'echo': [0, 0, 1, 2], 'speed': [0, 1, 2, 0], 'wall': [1, 0, 2, 3], 'strong concrete wall': [0, 0, 0, 1]}

The correct answer is option 3, 51m.

When a person rings a metallic bell near a strong concrete wall, the sound produced by the bell travels towards the wall and gets reflected back as an echo. The time taken for this round trip is given as 0.3s.

To calculate the distance between the person and the wall, we need to use the formula:

Distance = Speed x Time

Given that the speed of sound is 340 m/s and the time taken for the round trip is 0.3s, we can calculate the distance as:

Distance = 340 m/s x 0.3 s = 102 m

However, we need to remember that the distance calculated above is the total distance traveled by the sound, which includes the distance from the person to the wall and then back to the person. Since we are interested in the distance between the person and the wall, we need to divide the calculated distance by 2:

Distance = 102 m / 2 = 51 m

Therefore, the wall is located at a distance of 51 meters from the person.