Wave

Wave:

A wave is a disturbance that propagates through space and time, usually with transference of energy. Waves travel and transfer energy from one point to another, often with little or no permanent displacement of the particles of the medium (that is, with little or no associated mass transport); instead there are oscillations around almost fixed locations.

All waves have common behavior under a number of standard situations. All waves can undergo the following:

Reflection — change in wave direction after it strikes a reflective surface, causing the angle the wave makes with the reflective surface in relation to a normal line to the surface to equal the angle the reflected wave makes with the same normal line.

Refraction — change in wave direction because of a change in the wave's speed from entering a new medium.

Diffraction — bending of waves as they interact with obstacles in their path, which is more pronounced for wavelengths on the order of the diffracting object size.

Interference — superposition of two waves that come into contact with each other (collide).

Dispersion — wave splitting up by frequency.

Rectilinear propagation — the movement of waves in a straight line, in the absence of any obstacles or change in media.

Absorption — the wave energy is converted into some other form of energy, such as heat.

Formula:

The general solution for the wave equation in one dimension was given by d’Alembert; it is known as d’Alembert’s formula:

u ( x , t ) = F ( x – vt ) + G ( x + vt )

This formula represents two shapes traveling through the medium in opposite directions; F in the positive x direction, and G in the negative x direction, of arbitrary functional shapes F and G.

Frequency

Frequency:

Frequency in oscillation is the number of cycles per second, and in wave motion, it is the number of waves that pass through a given point per second. These cycles per second are called Hertz (Hz) in honor of nineteenth-century German physicist Heinrich Rudolf Hertz (1857-1894), who greatly advanced understanding of electromagnetic wave behavior during his short career.

Denotation:

In physics and technology disciplines, such as optics, acoustics, and radio, frequency is generally denoted by a Latin letter f or by a Greek letter ν (nu).

SI Unit:

In SI units, the unit of frequency is hertz (Hz), named after the German physicist Heinrich Hertz. 1 Hz means that a happening repeats one time per second. A previous name for this unit was cycles per second.

A customary unit of measure utilized with rotating mechanical devices is revolutions per minute, abbreviated RPM. 60 RPM equals one hertz.

Formula:

The time span, usually denoted by T, is the extent of time taken by one cycle, and is the reciprocal of the frequency f:

T=1/f

The SI unit for period is the second.

Capacitor

Capacitor:

A capacitor is a passive electronic component consisting of a pair of conductors separated by a dielectric. When a voltage potential difference exists between the conductors, an electric field is present in the dielectric. This field stores energy and produces a mechanical force between the plates. The effect is greatest between wide, flat, parallel, narrowly separated conductors.

Dielectric:

A basic capacitor is made up of two conductors separated by an insulator, or dielectric. The dielectric can be made of paper, plastic, mica, ceramic, glass, a vacuum or nearly any other non conductive material. Some capacitors are called electrolytic, meaning that their dielectric is made up of a thin layer of oxide formed on an aluminum or tantalum foil conductor.

Cautions:

Capacitors may retain charge long after power is removed from a circuit; this ascribe can origin unsafe or even potentially mortal alarms or damage attached gear. For example, even an apparently innocuous apparatus such as a disposable camera flash unit driven by a 1.5 volt AA electric battery contains a capacitor which may be ascribed to over 300 volts. This is effortlessly adept of delivering a shock.