These sources primarily discuss the field of Waves in Physics, exploring its fundamental concepts like oscillation, vibration, waves, and key wave properties such as amplitude, wavelength, period, frequency, and velocity. They categorize waves based on their nature (mechanical, electromagnetic), direction of vibration (transverse, longitudinal), and propagation dimensions. Several sources provide solved exercises related to these concepts and formulas for calculating wave characteristics, while also introducing various wave phenomena like reflection, refraction, and interference. One source also briefly mentions the historical development of wave mechanics and its connection to the dual nature of matter.