A person standing between two parallel cliffs fires a gun and hears two echoes, first echo after 1 second and the second echo after 3 second. The distance between the two cliffs is (Velocity of sound =340 ~m / s )

Step-by-step solution

Distance between cliffs using echo timing Given sound velocity v = 340 m/s , first echo time t₁ = 1 s , and second echo time t₂ = 3 s . Since each echo corresponds to sound traveling to a cliff and back, the distance to the first cliff is d₁ = v t₁ / 2 = 340 m/s 1 s / 2 = 170 m . Similarly, distance to the second cliff is d₂ = v t₂ / 2 = 340 m/s 3 s / 2 = 510 m . The total distance between cliffs is d₁ + d₂ = 170 m + 510 m = 680 m . Therefore, the distance is 680 m (Option B) .