JEE Main 2019 Physics question
A string is clamped at both the ends and it is vibrating in its 4th harmonic. The equation of the stationary wave is Y = 0.3 sin(0.157x) cos(200πt). The length of the string is: (All quantities are in SI units.)
Answer: (B)
Solution
k = 0.157 = π/20 ⇒ λ = 40 m; 4th harmonic: L = 4λ/2 = 80 m.