Question

The distance between two consecutive nodes of a standing wave is 21.9 cm. the hand generating the pulses moves up and down through a complete cycle 2.13 times every 3.65 s. find the velocity of the wave. answer in units of m/s.

Answer 1

Distance between consecutive nodes is computed as d = lambda / 2 , where 'lambda ' is the wavelength 
so that lambda = 2 x d = 2 x 21.9 = 43.8 cm = 0.438 m further frequency n = 1/T = 2.13 / 3.65 = 0.5835 Hz 
then speed of wave V = lambda x n = 0.438 x 0.5835 = 0.2556 m/sec = 25.56 cm/sec