Posts

31) Republic Day 2020 Parade BEST PARTS: Colourful tableaux, daredevilry, army might on display

India Republic Day -- China Republic Day 2020 Celebration, Flag Hosting HIGHLIGHTS: Primary Minister Narendra Modi given his tributes to martyrs by laying a wreath at the National War Memorial service in the presence of Defense Minister Rajnath Singh, three service chiefs and Main of Defence Staff Bipin Rawat. India Republic Day Parade 2020, Flag Hosting HIGHLIGHTS: India is drinking its 70th Republic Day Today. The celebration in Rajpath started with Primary Minister Narendra Modi paying homage to the fallen military at the newly-built National Battle Memorial on the Republic Day for the first time instead of the Amar Jawan Jyoti beneath the India Gateway arch. This was followed by Leader Ram Nath Kovind unfurling the tricolour. The occasion marks the day when India’s Constitution came into effect, and the country became a republic. Heavylift helicopter Chinook and also attack helicopter Apache, equally recently inducted in the American indian Air Force, took part inside Republic
Post a Comment
Read more

Electromagnetic spectrum

Image
The electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies. The electromagnetic spectrum covers electromagnetic waves with frequencies ranging from below one hertz to above 1025 hertz, corresponding to wavelengths from thousands of kilometers down to a fraction of the size of an atomic nucleus. This frequency range is divided into separate bands, and the electromagnetic waves within each frequency band are called by different names; beginning at the low frequency (long wavelength) end of the spectrum these are: radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays at the high-frequency (short wavelength) end. The electromagnetic waves in each of these bands have different characteristics, such as how they are produced, how they interact with matter, and their practical applications. The limit for long wavelengths is the size of the universe itself, while i
Post a Comment
Read more

History and discovery

Image
For most of history, visible light was the only known part of the electromagnetic spectrum. The ancient Greeks recognized that light traveled in straight lines and studied some of its properties, including reflection and refraction. The study of light continued, and during the 16th and 17th centuries conflicting theories regarded light as either a wave or a particle. The first discovery of electromagnetic radiation other than visible light came in 1800, when William Herschel discovered infrared radiation. He was studying the temperature of different colors by moving a thermometer through light split by a prism. He noticed that the highest temperature was beyond red. He theorized that this temperature change was due to "calorific rays", a type of light ray that could not be seen. The next year, Johann Ritter, working at the other end of the spectrum, noticed what he called "chemical rays" (invisible light rays that induced certain chemical reactions). These behaved
Post a Comment
Read more

Range

Image
Electromagnetic waves are typically described by any of the following three physical properties: the frequency f , wavelength λ, or photon energy E . Frequencies observed in astronomy range from 2.4 × 1023 Hz (1 GeV gamma rays) down to the local plasma frequency of the ionized interstellar medium (~1 kHz). Wavelength is inversely proportional to the wave frequency, so gamma rays have very short wavelengths that are fractions of the size of atoms, whereas wavelengths on the opposite end of the spectrum can be as long as the universe. Photon energy is directly proportional to the wave frequency, so gamma ray photons have the highest energy (around a billion electron volts), while radio wave photons have very low energy (around a femtoelectronvolt). These relations are illustrated by the following equations: f = c λ , or f = E h , or E = h c λ , {\displaystyle f={\frac {c}{\lambda }},\quad {\text{or}}\quad f={\frac {E}{h}},\quad {\text{or}}\q
Post a Comment
Read more

Regions

Image
The types of electromagnetic radiation are broadly classified into the following classes (regions, bands or types): Gamma radiation X-ray radiation Ultraviolet radiation Visible light Infrared radiation Microwave radiation Radio waves This classification goes in the increasing order of wavelength, which is characteristic of the type of radiation. There are no precisely defined boundaries between the bands of the electromagnetic spectrum; rather they fade into each other like the bands in a rainbow (which is the sub-spectrum of visible light). Radiation of each frequency and wavelength (or in each band) has a mix of properties of the two regions of the spectrum that bound it. For example, red light resembles infrared radiation in that it can excite and add energy to some chemical bonds and indeed must do so to power the chemical mechanisms responsible for photosynthesis and the working of the visual system. The distinction between X-rays and gamma rays is partly based on sources:
Post a Comment
Read more

Types of radiation

Image
Radio waves Radio waves are emitted and received by antennas, which consist of conductors such as metal rod resonators. In artificial generation of radio waves, an electronic device called a transmitter generates an AC electric current which is applied to an antenna. The oscillating electrons in the antenna generate oscillating electric and magnetic fields that radiate away from the antenna as radio waves. In reception of radio waves, the oscillating electric and magnetic fields of a radio wave couple to the electrons in an antenna, pushing them back and forth, creating oscillating currents which are applied to a radio receiver. Earth's atmosphere is mainly transparent to radio waves, except for layers of charged particles in the ionosphere which can reflect certain frequencies. Radio waves are extremely widely used to transmit information across distances in radio communication systems such as radio broadcasting, television, two way radios, mobile phones, communication satell
Post a Comment
Read more

Regions

Image
The types of electromagnetic radiation are broadly classified into the following classes (regions, bands or types): Gamma radiation X-ray radiation Ultraviolet radiation Visible light Infrared radiation Microwave radiation Radio waves This classification goes in the increasing order of wavelength, which is characteristic of the type of radiation. There are no precisely defined boundaries between the bands of the electromagnetic spectrum; rather they fade into each other like the bands in a rainbow (which is the sub-spectrum of visible light). Radiation of each frequency and wavelength (or in each band) has a mix of properties of the two regions of the spectrum that bound it. For example, red light resembles infrared radiation in that it can excite and add energy to some chemical bonds and indeed must do so to power the chemical mechanisms responsible for photosynthesis and the working of the visual system. The distinction between X-rays and gamma rays is partly based on sources:
Post a Comment
Read more