P, Q and R are three particles of a medium which lie on the x-axis. A sine wave of wavelength `lambda` is travelling through the medium in the x-direction. P and Q always have the same speed, while P and R always have the same velocity.
The minimum distance between –
(1) P and Q is `lambda`
(2) P and Q is `lambda//2`
(3) P and R is `lambda//2`
(4) P and R is `lambda`

Options

A. `P` and `Q` is `lamda//2`
B. `P` and `Q` is `lamda`
C. `P` and `R` is `lamda//2`
D. `P` and `R` is `lamda`

Answer

A, D