Assignment 09 Satellite Geodesy

Assignment 09 Satellite Geodesy 1. Electromagnetic Waves Electromagnetic waves are self-propagating waves that have magnetic and electrical components generated by rapid oscillations of electrically charged particles. Figure 1. Electromagnetic Waves (Source: Wikimedia) These waves travel at the speed of light in a harmonic form sinusoidal and propagates through a material medium generally with a resultant velocity less than the speed of light. a. Properties of Electromagnetic Waves. Electromagnetic waves have several properties, namely: - Electromagnetic waves are transverse waves. - Changes in the electric field E and magnetic field B occur at the same time. - The directions of the electric field E and magnetic field B are perpendicular to each other. - The strength of the electric field E and the magnetic field B are directly proportional to each other another. - The direction of propagation of electromagnetic waves is always perpendicular to the direction of the electric field E and magnetic field B. - Electromagnetic waves can propagate in a vacuum. - The rate of propagation of electromagnetic waves in a vacuum is a constant general (constant) c = 3 x 108 m/s. - Electromagnetic waves can experience the processes of reflection, refraction, polarization, interference, and diffraction (bending). b. Source of Electromagnetic Waves. - Electrical oscillations, which are the manifestation of a coil rotating about the environment has a magnetic field and will produce electric currents and electric fields which changes regularly. This change in the electric field will also cause electromagnetic wave patterns. - Sunlight produces infrared rays, visible light and ultra violet rays. - Infrared lamps that specifically produce infrared rays. - Ultraviolet lamps that specifically produce ultraviolet light. - Shooting electrons in a vacuum tube at a metal chip produces X-rays - The atomic nucleus is unstable, resulting in alpha, beta and gamma radiation (is one of the electromagnetic waves). c. Magnetic Wave Radiation Spectrum Figure 2. Electromagnetic Wave Spectrum The electromagnetic wave radiation spectrum is the entire range of electromagnetic wave radiation which is the product of radioactive atoms. Wave energy is very dependent on the wavelength itself. The longer the wave, the higher the energy. This can be formulated as follows: 𝐸 = ℎ𝑓 = ℎ𝑐: λ Where, h = Plank Constant (6.626 x 10-34 Js) f = Frequency c = Speed of light There are several types of electromagnetic waves, including: - Radio Wave Figure 3. Radio Wave Transmitters in the Atmospheric Layer (Source: lancangkuning.id) Electromagnetic waves were first discovered by Heinrich Hertz and used by Marconi as a communication medium were radio waves. Radio wave frequencies from AM (Amplitude Modulation) to FM (Frequency Modulation) ranges from 102 up to 109 Hz. - Microwaves (Microwaves) Figure 4. Microwave Region of the Electromagnetic Spectrum (Source: emodul.kemdikbud.go.id) Microwaves are electromagnetic waves with super high frequency (Super High Frequency), namely above 3 GHz (3×109 Hz). Microwaves are used as Radar (Radio Detection and Ranging). Radar is used to search for and determine the traces of an object using waves micro at a frequency of about 1010 Hz, or a wavelength of about 3 cm. - Infrared Waves (Infra Red) Figure 5. Infrared Wave Region of the Electromagnetic Spectrum) (Source: emodul.kemdikbud.go.id) Infrared is a long electromagnetic wave waves are longer than visible light, but shorter than light waves radio which is around 1000 nm to 1 mm. Infrared rays cover the frequency region 1011 Hz to 1014 Hz or wavelength region 10-4 cm to 10-1 cm. - Visible Light Figure 6. Visible Light Region of the Electromagnetic Spectrum) (Source: emodul.kemdikbud.go.id) Visible light waves are electromagnetic waves that can seen by the human sense of sight. Visible light waves consist of with the following wavelengths: • Red: 620 – 780 nm • Orange: 590 – 620 nm • Yellow: 570 – 590 nm • Green: 490 – 570 nm • Blue: 450 – 490 nm • Indigo: 420 – 450 nm • Purple: 380 – 420 nm - X-rays (X-ray) Figure 7. X-ray Region of the Electromagnetic Spectrum) (Source: emodul.kemdikbud.go.id) X-rays have extraordinary penetrating power, able to penetrate structures soft like flesh and wood, except for solid structures like bone. Long X-ray waves between 0.03 nm to 3 nm. - Gamma rays (Gamma rays) Figure 8. Gamma ray Region of the Electromagnetic Spectrum) (Source: emodul.kemdikbud.go.id) Gamma ray waves (usually written as γ rays) are waves the strongest electromagnetic wave among other electromagnetic waves γ ray waves can penetrate solid structures, and can even change the structure atoms into different atoms. The wavelength of Ү rays ranges from 0.0003 nm to 0.03 nm.