This unit includes the terms associated with periodic motion, the harmonic motion is described with the help of common examples. A qualitative idea of forced oscillations, resonance and damped oscillations is also given.

- Periodic Motion
- Simple Harmonic Motion: Circle of Reference
- Basic Terms Associated with SHM
- Oscillations of a Spring-Mass System
- Simple Pendulum
- Energy of Simple Harmonic Oscillator
- Damped Harmonic Oscillations
- Free and Forced Vibrations: Resonance

- Propagation of Transverse Waves
- Propagation of Longitudinal Wave
- Equation of Simple Harmonic Wave in One Dimension
- Transverse and Longitudinal Waves
- Velocity of Sound in a Gas
- Laplace’s Correction
- Factors Affecting Velocity of Sound in Gas
- Velocity of Waves in Stretched Strings
- Superposition of Waves
- Reflection and Transmission of Waves
- Interference of Waves
- Beats
- Formation of Stationary (Standing) Waves
- Equation of Stationary Wave
- Distinction Between Travelling and Standing Waves
- Characteristics of Musical Sound
- Organ Pipes
- Properties of Electromagnetic Waves
- Electromagnetic Spectrum
- Doppler Effect