Question

Length of a string tied to two rigid supports is $40 cm .$ Maximum length (wavelength in $cm$ ) of a stationary wave produced on it, is :

• A. 20
• B. 80
• C. 40
• D. 120

Answer 1

Answer: (B)

80

Answer 2

When the string is plucked in the middle, it vibrates in one loop with nodes at fixed ends and an antinodc in the middle. So that, $\frac{\lambda_{1}}{2}=l$ $\lambda_{1}=2 \times 40=80$ cm