
$A \rightarrow(p, t):$ It is a closed organ pipe hence in case of fundamental vibrations length of the tube must be $\left(\frac{1}{4}\right)^{\text {th }}$ of the wavelength (half loop).
$\frac{\lambda_t}{4}=L \Rightarrow \lambda_t=4 L$
$B \rightarrow(p, s)$ : It is open organ pipe hence in case of fundamental vibrations length of the pipe must be half of the wavelength (one loop).
$\frac{\lambda_t}{2}=L \Rightarrow \lambda_t=2 L$
$C \rightarrow(q, s)$ : It is a case of string of length $L$ fixed at both ends.
In case of fundamental vibrations length of the pipe must be half of the wavelength (one loop).
$\frac{\lambda_t}{2}=L \Rightarrow \lambda_t=2 L$
$D \rightarrow(q, r):$ In this case mid-point is fixed hence half-length must form one loop.
$\frac{\lambda_t}{2}=\frac{L}{2} \Rightarrow \lambda_t=L$
${z_1},{z_2}$ and ${z_3}$ as${z_1} = A\sin (kx - \omega \,t)$, ${z_2} = A\sin (kx + \omega \,t)$ and ${z_3} = A\sin (ky - \omega \,t)$.
Which of the following represents a standing wave
$(a)$ Every particle has a fixed amplitude which is different from the amplitude of its nearest particle.
$(b)$ All the particles cross their mean position at the same time.
$(c)$ All the particles are oscillating with same amplitude.
$(d)$ There is no net transfer of energy across any plane.
$(e)$ There are some particles which are always at rest.
Which of the following is correct