Two identical progressive waves moving in opposite directions superimpose to produce a stationary wave. The wavelength of each progressive wave is $\lambda$. The wavelength of the stationary wave is

Two progressive waves $Y_1 = \sin 2 \pi \left( \frac{t}{0.4} - \frac{x}{4} \right)$ and $Y_2 = \sin 2 \pi \left( \frac{t}{0.4} + \frac{x}{4} \right)$ superpose to form a standing wave. $x$ and $y$ are in $SI$ units. The amplitude of the particle at $x = 0.5 \ m$ is $\left[ \sin 45^{\circ} = \cos 45^{\circ} = \frac{1}{\sqrt{2}} \right]$.

The distance between the nearest node and antinode in a stationary wave is

At nodes in stationary waves,

Which of the following statements is true regarding stationary waves?

What are the amplitudes at node and antinode in a stationary wave? Explain.