1. The sine wave is produced by the up-and-down motion of a piston or electrical coil and displays a repeating wave pattern over time. 2. Characteristics of the sine wave include its phase or position in the wave cycle, amplitude or maximum displacement from center, wavelength or distance between peaks, frequency or number of waves per second, and velocity. 3. Electromagnetic waves like light and radio waves can be described as sine waves with characteristics like frequency, wavelength, and velocity depending on the type of radiation.

1. SINE WAVE AND WAVE PATTERNS
MOHAMED ANWER RIFKY

2. The Sine Wave and Wave
Patterns
MOHAMED ANWER RIFKY
THE CONCEPT OF A SINE WAVE:
1-We have different types of simple wave forms (the sine wave, the sawtooth wave, and the square
wave)-Sine wave is of special importance as we produce any of the other patterns by combining
together various different sine waves.
2-The movement of the coil in an electrical generator produces a sine wave (alternating current), and also be pump with a piston moving up
and down with the movement of a crankshaft >>sine of angle A=d/r >>d=r sin A-angle. A has a different value as the crank is rotating at a
constant rate>>graph(d and angle of A)>>SINE WAVE PATTERN.
.CHARACTERISTICS OF THE SINE WAVE:
A-Phase
The angles of A along the horizontal axis >>phase of the sine wave. One complete rotation of the pump crankshafter>>results in one complete cycle on
the graph=360° ,and a rotation of the crank through 180° is half a cycle. If two sine waves differ by exactly one-quarter of a cycle or 90°, and so they are
said to be 90° out of phase.
B-Wavelength and Amplitude
The wavelength is the distance between any two corresponding points in successive cycles (between two peaks). The maximum displacement of the
wave from the horizontal axis is known as its amplitude. In case of sound waves, a large amplitude is loud and a small amplitude quiet, whereas with
light waves a large amplitude is bright and a small amplitude dim.
C-Frequency, Period and Velocity
The frequency (number of complete cycles which occur in 1 second >>SI systemis cycles per second (hertz or Hz).10 cycles per second =ten
complete cycles occur in 1 second, the time taken for each cycle is one-tenth of a second- t-1/f , where t = period f = frequency
Velocity = Frequency x Wavelength -10 Hz with a wavelength of 1 m>> the velocity = 10 m s-1 -Sound, has a velocity of 330 m s-1 in air. If the
velocity is fixed, then frequency and wavelength are inter-related, the higher the frequency, the shorter the wavelength and vice versa.
A sound wave with a high frequency has a short wave length >>high pitched note, whereas a sound with a low frequency (longer wavelength) >>low
pitched. The behaviour of light can also be explained in terms of wave motions. A light wave motion with a high frequency and a short wavelength is
seen as blue, whereas one with a lower frequency and longer wave length appears red.
Visible light is a small part of the electromagnetic spectrum, which also includes radio waves, infrared and ultraviolet radiation, X-rays and gamma
rays.. The velocity of electromagnetic radiation is constant in a vacuum for all frequencies and is equal to 3 x 108 m s-1. In solids and liquids it is
slower, but in gases such as air the reduction in velocity is so small that the wavelength can be regarded as the velocity in a vacuum divided by the
frequency. Radio waves are quoted as a frequency, up to 109 Hz (1GHz) and infrared, visible and ultraviolet radiations as a wavelength usually in μπι
or nm. For X-rays and gamma rays a unit of energy called the electron-volt (eV) is used (see SI.), the energy of a wave being equal to a constant
times its frequency. X-rays and gamma rays of clinical interest have energies ranging from keV to MeV. Various uses of the different electromagnetic
radiations( paging systems and the technique of remote monitoring) . Gases are capable of absorbing infrared radiation( CO2& N20),and infrared
radiation is also used to form images in thermography. Gamma rays and X-rays are essential to radiology and are used in radiotherapy and nuclear
medicine. Visible light is also used (oximeter used to measure oxygen saturation in blood and inrefractometry). Gases emit electromagnetic radiation if
they are suitably excited (wavelengths of radiation emitted >> detect the gas). In the SI system the second is defined in terms of the frequency of
radiation emitted by atoms of caesium-133.