Question

A sine wave is travelling in a medium. A particular particle has zero displacement at a certain instant. The particle closest to it having zero displacement is at a distance
(a) $\lambda /4$
(b) $\lambda /3$
(c) $\lambda /2$
(d) $\lambda$.

Answer 1

(c) $\lambda /2$

A sine wave has a maxima and a minima and the particle displacement has phase difference of π radians. Therefore, applying similar argument we can say that if a particular particle has zero displacement at a certain instant, then the particle closest to it having zero displacement is at a distance is equal to $\lambda /2$.