WAVES
Frequently Asked Questions
A wave is a disturbance that propagates through a medium or space and transfers energy without causing any permanent displacement of matter.
Wave motion is the propagation of oscillations from one point to another in a medium due to restoring forces and inertia of particles.
No, wave motion involves transfer of energy only; particles oscillate about their mean positions.
Mechanical waves are waves that require a material medium for propagation, such as sound waves and water waves.
Non-mechanical waves do not require a material medium and can propagate through vacuum, for example electromagnetic waves.
Transverse waves are waves in which particles of the medium oscillate perpendicular to the direction of wave propagation.
Waves on a stretched string, ripples on the surface of water, and electromagnetic waves are examples.
Longitudinal waves are waves in which particles of the medium oscillate parallel to the direction of wave propagation.
Sound waves in air and compression waves in solids are examples of longitudinal waves.
Wavelength is the distance between two successive points in the same phase of vibration, such as consecutive crests or compressions.
The SI unit of wavelength is metre (m).
Frequency is the number of complete oscillations made by a particle of the medium per second.
The SI unit of frequency is hertz (Hz).
Time period is the time taken by a particle of the medium to complete one full oscillation.
Frequency is the reciprocal of time period, given by \( f = \frac{1}{T} \).
Wave velocity is the speed with which a disturbance travels through a medium.
The wave velocity is given by \( v = f\lambda \).
Wave speed depends on the properties of the medium such as elasticity and density.
No, wave speed does not depend on amplitude in a linear medium.
Amplitude is the maximum displacement of a particle from its equilibrium position during oscillation.
Amplitude represents the energy carried by the wave; greater amplitude means higher energy.
A wave equation mathematically describes the variation of displacement with position and time for a wave.
The standard wave equation is \( y(x,t) = A\sin(kx - \omega t + \phi) \).
Angular frequency is the rate of change of phase of the wave, given by \( \omega = 2\pi f \).
Wave number is the number of wavelengths per unit distance, given by \( k = \frac{2\pi}{\lambda} \).
Phase represents the state of oscillation of a particle at a given time and position.
Two waves are in phase if their phase difference is zero or an integral multiple of \(2\pi\).
Phase difference is the difference in phase between two oscillating particles or waves.
Progressive waves are waves that travel through a medium carrying energy from one point to another.
Stationary waves are formed by superposition of two identical waves traveling in opposite directions.
No, stationary waves do not transport energy along the medium.
Nodes are points where the displacement is always zero.
Antinodes are points where the displacement is maximum.
The distance between two consecutive nodes is \( \frac{\lambda}{2} \).
The distance between a node and the nearest antinode is \( \frac{\lambda}{4} \).
When two or more waves overlap, the resultant displacement is the vector sum of individual displacements.
Interference is the phenomenon of redistribution of wave intensity due to superposition of waves.
Constructive interference occurs when waves combine to give maximum resultant amplitude.
Destructive interference occurs when waves combine to give minimum or zero resultant amplitude.
Beats are periodic variations in sound intensity due to interference of two waves of slightly different frequencies.
Beat frequency is the difference between the frequencies of the two interfering waves.
Sound waves are longitudinal mechanical waves produced by vibrating bodies and propagated through a medium.
Sound requires a material medium for propagation; hence it cannot travel in vacuum.
Pitch depends on the frequency of the sound wave.
Loudness depends on the amplitude or intensity of the sound wave.
Resonance occurs when a system vibrates with maximum amplitude at its natural frequency due to an external periodic force.
Forced vibration is vibration of a body under the influence of an external periodic force.
Harmonics are frequencies that are integral multiples of the fundamental frequency.
The fundamental mode is the lowest frequency mode of vibration of a system.
This chapter builds conceptual and mathematical foundations for sound, optics, and modern physics and is frequently tested in numerical and conceptual problems.
