# HC Verma for Class 11 Physics Chapter 16:Sound Waves

Chapter 16 Sound waves deals entirely with a sound that propagates through the transmission medium. Sound is a wave that is created by vibrating objects and propagated through a medium from one location to another. In physics, it is also considered that sound is produced in the form of a pressure wave. A sound wave's speed depends on the type of medium it is travelling through and its state. A sound wave is typically affected by two things: elasticity and inertia.

Sound waves are longitudinal waves. This implies that the vibration of the wave particles is parallel to the direction in which the energy wave propagates. The sound particles move back and forth when vibrating. Such motion results in creating a high- pressure and a low-pressure region in the medium.

There are few important notations to be considered while learning about sound waves, such as frequency, wavelength, etc. For example, the frequency of a sound wave can be defined as the number of rarefactions and compressions that occur per unit of time. Similarly, the wavelength of a sound wave can be defined as the distance between successive compressions and rarefactions. On the other hand, the amplitude of a sound wave is the magnitude of the maximum disturbance in a sound wave. The amplitude is also used to measure energy. The higher the amplitude, the higher is the energy in a sound wave.

This chapter further focuses on the concept of intensity. The intensity of a sound wave can be defined as the amount of energy transported over a unit area per unit of time. The higher the amplitude of vibrations of the particles in the medium, the higher is the intensity. Sound waves typically carry energy through two-dimensional and three-dimensional mediums. Therefore, as the distance from the source increases, the intensity of the sound wave also decreases.