Ten JEE Main and JEE Advanced questions on waves: the power carried by a wave on a string, the speed of sound in a mixture of gases, a whistle whirled in a circle, a pulse meeting a heavier string, a car heard as it passes, the energy of a standing wave, a standing wave read from its equation, a source moving towards a wall, the length of a pipe from two resonances, and a stretched steel wire. Most have one correct option; two have one or more, and two ask for a number. Every question has a hint and a full worked solution.