Physics Chapter 1: Introduction to Waves

What is a Wave?

• A wave is a disturbance in a medium that carries energy without a net movement of particles.
• It can take the form of elastic deformation, variation of pressure, electric or magnetic intensity, electric potential, or temperature.

Descriptors of a Wave

• Wavelength is the distance between an identical part of the wave.
• Amplitude is the maximum displacement from the neutral position, representing the energy of the wave.
• Greater amplitude carries greater energy.
• Displacement is the position of a particular point in the medium as it moves when the wave passes.
• Maximum displacement is the amplitude of the wave.

Frequency and Period

• Frequency (ƒ) is the number of repetitions per second in Hz, s -1.
• Period (T) is the time for one wavelength to pass a point, T = ƒ-1.

Velocity of a Wave

• The velocity (v) of the wave is the speed that a specific part of the wave passes a point.
• The speed of a light wave is c.

Introduction to Sound

• Sound is a vibration that propagates as an acoustic wave through a transmission medium such as a gas, liquid, or solid.
• In human physiology and psychology, sound is the reception of such waves and their perception by the brain.

Properties of Sound Waves

• Only acoustic waves with frequencies between about 20 Hz and 20 kHz, the audio frequency range, elicit an auditory percept in humans.
• In air at atmospheric pressure, these represent sound waves with wavelengths of 17 meters (56 ft) to 1.7 centimeters (0.67 in).
• Sound waves above 20 kHz are known as ultrasound and are not audible to humans.
• Sound waves below 20 Hz are known as infrasound.

Longitudinal Waves

• A longitudinal wave has the movement of the particles in the medium in the same dimension as the direction of movement of the wave.
• Examples of longitudinal waves: Sound waves, P-type earthquake waves, Compression wave.
• Parts of longitudinal waves: Compression (where the particles are close together) and Rarefaction (where the particles are spread apart).

Transverse Waves

• Waves in which the medium moves at right angles to the direction of the wave.
• Examples of transverse waves: Water waves, Light waves, S-wave earthquake waves, Stringed instruments, Torsion wave.
• The high point of a transverse wave is a crest, and the low part is a trough.

Periodic Waves

• A periodic wave is a wave with a repeating continuous pattern which determines its wavelength and frequency.
• It is characterized by the amplitude, a period, and a frequency.
• Amplitude wave is directly related to the energy of a wave, it also refers to the highest and lowest point of a wave.
• Period defines as time required to complete cycle of a waveform, and frequency is the number of cycles per second of time.

Test your understanding of the fundamental concepts of waves, including wavelength, amplitude, and energy. Learn about the different types of waves and their characteristics in this introductory physics quiz.