No, nodes on a standing wave do not necessarily have to be of zero amplitude. In a standing wave, nodes are the points of minimal displacement or amplitude. However, it is possible for the amplitude at a node to be nonzero, depending on the specific conditions of the wave.
In a simple standing wave, such as a vibrating string or a sound wave in a closed tube, the nodes are locations where the wave experiences complete destructive interference. At these points, the displacements of particles or the amplitudes of the wave are minimized. In idealized situations, nodes are often considered to have zero amplitude.
However, in real-world scenarios, factors such as imperfections in the medium or environmental conditions can introduce some non-zero amplitude at the nodes. These factors can lead to partial destructive interference, causing a small but nonzero amplitude at the nodes. Nonetheless, the amplitude at the nodes is still significantly lower than the amplitude at other points in the standing wave, such as the antinodes where the displacement is maximized.
It's important to note that the concept of nodes in a standing wave primarily refers to points of minimum displacement or amplitude, regardless of whether they are exactly zero or have a small nonzero value in practice.