Answer:
The wall is 680 meter away from the person.
Explanation:
Given data
Speed of sound = 340 
Given that Persons said hello toward the opposite side she has an echo hello 4 seconds later means it takes 2 seconds for the sound to reach the wall & again 2 seconds to reach the persons ear.
Therefore the distance between the person & wall is
D = speed × Time
D = 340 × 2
D = 680 meter
Therefore the wall is 680 meter away from the person.
The quarks that compose a baryon may have charges of +(2/3)e and -(1/3)e which means have negative and positive charges.
<h3>What are quarks?</h3>
Quarks are the most fundamental particles that make up the atomic nucleus. All solid matter that we know is made of three particles, which are the up and down quarks, 'u' and 'd', and the electron.
Quark is one of the two basic elements that make up matter and is the only one of the particles that interacts through all four fundamental forces.
See more about quarks at brainly.com/question/1444547
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The symbol "E3" represents the energy of electrons in the third energy level.
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Your fluid intake is enhanced, you feel refreshed, you get a sugar high for a while, and a lot if the rust is removed from your stomach and small intestine.
