Ch 14Waves — Class 11 Physics, concept-first.

WBCHSE's Unit 10, "Oscillation and Waves", studies periodic motion in two stages. SUB TOPIC 1 examines simple harmonic motion (SHM) in an isolated oscillating system -- a pendulum, a mass on a spring…

A wave is a disturbance that travels through a medium (or, for electromagnetic waves, through empty space) carrying energy and momentum from one point to another without any net displacement of the me…

Mechanical waves are classified into two kinds according to the relation between the direction in which the medium's particles vibrate and the direction in which the wave itself propagates.

A progressive (or travelling) wave is one that carries its disturbance steadily onward through the medium, in contrast to the stationary wave met later in this chapter.

The wavelength of a progressive wave is the distance, measured along the direction of propagation, between two nearest points of the medium that are in exactly the same phase of oscillation at a given…

The period of a progressive wave is the time taken by any one particle of the medium to complete one full cycle of its oscillation, and the frequency is the number of complete oscillations that partic…

It is essential to distinguish the wave speed from the frequency or wavelength individually: while connects the three quantities kinematically, the speed at which a mechanical wave travels through a g…

For a transverse wave travelling along a taut string, the elastic (restoring) property is provided by the tension in the string -- it is the tension that pulls a displaced element of the string back t…

Sound travels through a gas such as air as a longitudinal wave, so the relevant elastic property is the gas's bulk modulus (which measures its resistance to compression) and the relevant inertial prop…

The principle of superposition of waves states that when two or more waves travel through the same region of a medium simultaneously, the resultant (net) displacement of any particle of the medium, at…

A travelling wave is reflected whenever it meets a boundary -- a change from one medium to another, or the end of a bounded medium such as a string or an air column.

Consider a string of length , rigidly fixed at both ends -- the situation in every stringed instrument and in the standard sonometer experiment.

An organ pipe is a tube of air, open at one or both ends, inside which a longitudinal stationary wave can be set up by blowing air across an opening (or over a reed) at one end, exciting the enclosed…

In a pipe open at both ends, both ends must be displacement antinodes. Since an antinode-to-antinode spacing (like a node-to-node spacing) is , the pipe's length must fit a whole number of half-wavele…

In a pipe closed at one end and open at the other, the closed end must be a displacement node while the open end must be a displacement antinode.

When two sound waves of slightly different, but close, frequencies and travel through the same medium and arrive together at a point, their superposition produces a periodic waxing and waning of loudn…

The Doppler effect is the change in the frequency of a wave as perceived by an observer, occurring whenever there is relative motion between the source of the wave and the observer along the line join…

With the observer stationary (), the general Doppler formula reduces to If the source moves TOWARD the stationary observer at speed , the denominator becomes (smaller than ), so -- the observer hears…

With the source stationary (), the general Doppler formula reduces to If the observer moves TOWARD the stationary source at speed , then -- a higher pitch is heard, because the moving observer interce…

When both the source and the observer are simultaneously in motion along the line joining them, the two corrections combine into the fully general Doppler formula introduced above, with each of and ca…

A mechanical wave is a disturbance carrying energy through an elastic, inertial medium without net transport of the medium's own matter; in a transverse wave particles vibrate perpendicular to propaga…

Sample papers and previous-year board questions for this subject.