Physics · Waves · NEET
It is a real, observable pattern, but it is formed by superposition. When a travelling wave hits a fixed end and reflects, the original wave and the reflected wave (same amplitude, same frequency, opposite direction) overlap. Their sum gives the standing wave. So a standing wave is always the result of two travelling waves. The equation shows this: y = 2a sin(kx) cos(wt). The sin(kx) part fixes the shape in space; the cos(wt) part makes every point oscillate in time.
In a travelling wave, each particle passes its energy to the next particle ahead, so energy flows in the direction of travel. In a standing wave, the two overlapping waves carry equal energy in opposite directions, so the net energy flow is zero. Energy is not transported forward; it only sloshes back and forth between kinetic form (at antinodes) and potential form (near nodes), staying trapped between the nodes. This is why NEET calls it a stationary wave.
No, and this is the most tested point. In a standing wave the amplitude changes with position: it is zero at nodes and maximum at antinodes. But all particles between two nodes move in the same phase (they reach maximum together and zero together), and particles in the next segment are exactly out of phase. In a travelling wave, every particle has the SAME amplitude, but each one has a slightly different phase, so a moving profile is seen.
No. A node is a point that never moves at all (amplitude = 0 permanently). A travelling wave has no such permanently fixed point; every particle oscillates with full amplitude, just at different times. Nodes exist only in standing waves and are spaced half a wavelength apart. Antinodes (maximum amplitude) sit exactly between nodes.
Look at how x and t appear. Travelling wave: x and t are together inside one bracket, like y = a sin(kx - wt). You cannot separate space and time. Standing wave: x and t are in separate factors, like y = 2a sin(kx) cos(wt) - a space part multiplied by a time part. If you can split it into (function of x) x (function of t), it is a standing wave.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
A travelling wave moves forward through the medium and transports energy; its waveform shifts with time. A standing wave stays in one place, transports no net energy, and shows fixed nodes (zero motion) and antinodes (maximum motion).
A standing wave forms when two waves of the same amplitude and frequency travel through the same medium in opposite directions and superpose. This usually happens when a travelling wave reflects from a boundary, such as the fixed end of a string or the closed end of a pipe.
No. In a standing wave amplitude depends on position: it is zero at nodes and maximum (2a) at antinodes. In a travelling wave, every particle has the same amplitude but a different phase.
The wave pattern does not move forward - nodes and antinodes stay in fixed positions. But the particles of the medium still oscillate up and down in place between the nodes.
Only a travelling (progressive) wave transports energy from one point to another. A standing wave stores energy locally and shows zero net energy transport.
