A string of length 1 . 5 m with its two ends clamped is vibrating in the fundamental mode. The amplitude at the centre of the string is 4 mm . The minimum distance between the two points having amplitude of 2 mm is:

Step-by-step solution

λ = 2 L = 3   m Equation of standing wave y = 2 A sin k x cos ω t y = A as amplitude is 2 A . A = 2 A sin k x 2 π λ x 1 = π 6 ⇒ x 1 = 1 4   m And 2 π λ x 2 = 5 π 6 ⇒ x 2 = 1.25   m ⇒ x 2 - x 1 = 1   m