Question 7: How might one can locate the position of node and anti-node on a vibrating string?
Nodes in a standing wave produced in a string happen on equally spaced intervals. The amplitude of the waves is zero at these locations. At all these points, two anti-phase waves add together and cancel out each other. At a vibrating string the fixed ends force the wave to stop. Therefore, the fixed ends are always nodes. Along the vibrating string, other nodes occur at intervals equal to half the wavelength of the wave, i-e, λ/2.
Antinodes are those points of the string which have maximum amplitudes. All anti-nodes are midway between the nodes. Therefore, they are also at a distance of λ/2 from each other. Thus if both ends of the vibrating string are fixed, two nodes will be formed at the fixed ends of the string and the other nodes along the string will be at distances λ/2 from one another.
Similarly, the antinodes will be midway between the two consecutive nodes. The interval between the two consecutive antinodes also will be λ/2.
If one end of the string is free, the free end will make an anti-node.