Q. The Stationary wave produced on a string is represented by the equation $y = 5 \cos \left(\frac{\mathrm{\pi x}}{3}\right) \sin \left(40\mathrm{\pi l}\right)$ where 'x' and 'y' are in cm and 't' is in seconds. The distance between consecutive nodes is :

(1) 5 cm                                         (2) $\mathrm{\pi }$ cm

(3) 3 cm                                         (4) 40 cm