A taut string of length 1.8 m is fixed at both ends. During a laboratory investigation, a standing-wave pattern is produced on the string. A student identifies one configuration as the "second harmonic."
(a) Describe the physical difference between a node and an antinode for the standing wave on the string.
(b) Explain, with reference to wave superposition, why the distance between two adjacent nodes on the string equals one-half of the wavelength for that harmonic.
(c) Sketch the qualitative shape of the third harmonic for this string. Clearly label all nodes and antinodes and indicate the direction of the string’s length on your sketch.