Question

The physical quantity, which oscillates in most waves, is

Answer 1

Mass oscillates in mechanical waves like pressure waves, or sound waves caused due to vibration. There is no mass oscillating in an electromagnetic wave. Amplitude is a fixed quantity for a constant wave of a frequency. The amplitude could oscillate (vary periodically) if there are multiple frequencies in a wave

Answer 2

The physical quantity, which

oscillates in most waves, is

pressure wave or sound wave

caused due to vibration.