A string of length 0.4 m and mass 10-2 kg is clamped at its ends. The

1.	A string of length 0.4 m and mass 10-2 kg is clamped at its ends. The tension in the string is 1.6 N. When a pulse travels along the string, the shape of the string is found to be the same at times t and t + Δt. The value of Δt is (a) 0.05 s (b) 0.1 s (c) 0.2 s (d) 0.4 s
Answer» Correct Answer is: (b) 0.1 s Wave velocity on string = V = √(1.6/(10^-2/0.4)) =8 /s.m For the string to regain its shape, the pulse must travel a distance which is twice the length of the string, as the pulse gets inverted at each reflection from a fixed end. ∴ t = 2 x 0.4 m / 8 m/s = 0.1 s.

A string of length 0.4 m and mass 10-2 kg is clamped at its ends. The tension in the string is 1.6 N. When a pulse travels along the string, the shape of the string is found to be the same at times t and t + Δt. The value of Δt is (a) 0.05 s (b) 0.1 s (c) 0.2 s (d) 0.4 s

Answer»

Correct Answer is: (b) 0.1 s

Wave velocity on string = V = √(1.6/(10^-2/0.4)) =8 /s.m

For the string to regain its shape, the pulse must travel a distance which is twice the length of the string, as the pulse gets inverted at each reflection from a fixed end.

∴ t = 2 x 0.4 m / 8 m/s = 0.1 s.

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A string of length 0.4 m and mass 10-2 kg is clamped at its ends. The tension in the string is 1.6 N. When a pulse travels along the string, the shape of the string is found to be the same at times t and t + Δt. The value of Δt is (a) 0.05 s (b) 0.1 s (c) 0.2 s (d) 0.4 s

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