Question

A wave pulse is travelling on a string whose length is $0.7m$ and linear mass density $6.4\times 10^{- 3}kgm^{- 1}$ under a load of $80kgf$ . Calculate the time taken by the pulse to traverse the string?

• A. 2 × 10^-3 s
• B. 3 × 10^-3 s
• C. 4 × 10^-2 s
• D. 5 × 10² s

Answer 1

Answer: (A)

Here, $\text{T = 80}$ kgf = $\text{= 80 }\times \text{ 9}\text{.8 }$ N ;
$m =6.4 \times 10^{-3} kg m ^{-1}$
$Now, \upsilon = \sqrt{\frac{\text{T}}{\text{m}}} = \sqrt{\frac{8 0 \times 9 \cdot 8}{6 \cdot 4 \times 1 0^{- 3}}} = 3 5 0 \text{m } \text{s}^{-1}$
Therefore, time taken by the wave pulse to traverse 0.7 m length of the string,
$t = \frac{ l }{\upsilon} = \frac{\text{0} \text{.} 7}{3 5 0} = 2 \times 1 0^{- 3}$ s