Raman Scattering or Raman Effect is the inelastic scattering of a photon. This was first reported by CV Raman for which he was awarded the Nobel prize in 1930. When light is scattered from an atom or a molecule, most photons scatter elastically. However, a small fraction (1 in a million) is scattered inelastically. The frequency of these photons changes, …
Read More »खिलौनों की सबसे बड़ी और पुरानी दुकान – Hamleys Toy Store
लंदन की रीजेंट स्ट्रीट पर स्थित हैमलेज दुनिया की अपने तरह की सबसे बड़ी और सबसे पुरानी खिलौनों की दुकान है। यहाँ अरब देशों के रईस शेख अपने बच्चों के लिए सबसे लेटेस्ट खिलौने खरीदने आतें हैं तो रूसी कुलीन वर्ग के लोग भी अपने बच्चों के लिए ट्रक भर कर यहीं से खिलौने ले जाते हैं। असल में यह …
Read More »What is radar used for?
Radar, or radio location, as it was called in the early days, is the use of radio waves to find the whereabouts of aircraft or ships. Electromagnetic waves, which include radio and light waves, all travel at the same speed. When small bursts of radio waves, fired into space from a transmitter, strike an object such as an aircraft some …
Read More »What is quasi-resonance?
A ‘quasi-resonant’ DC to DC converter with zero-current and zero-voltage switching includes a transformer with primary and secondary windings, and periodic switching means connected in series with the primary winding. The topology of the converter is determined by selecting an input capacitor with a capacitance much lower than the output capacitor.
Read More »17 मार्च – बलिदान दिवस – आजाद हिन्द फौज के सेनानी लेफ्टिनेंट ज्ञानसिंह बिष्ट
द्वितीय विश्व युद्ध में अंग्रेजों एवं मित्र देशों की सामरिक शक्ति अधिक होने पर भी आजाद हिन्द फौज के सेनानी उन्हें कड़ी टक्कर दे रहे थे. लेफ्टिनेंट ज्ञानसिंह बिष्ट भी ऐसे ही एक सेनानायक थे, जिन्होंने अपने से छह गुना बड़ी अंग्रेज टुकड़ी को भागने पर मजबूर कर दिया. 16 मार्च, 1945 को ‘सादे पहाड़ी के युद्ध’ में भारतीय सेना …
Read More »What is Push to Talk feature in mobile phones?
Push to Talk (PTT), also known as press to transmit, is a method by which we can communicate on halfduplex communication lines, including two-way radio, using a momentary button to switch from voice reception mode to transmit mode. A two-way radio can both transmit and receive (a transceiver), unlike a broadcast receiver which only receives content. Two mobile phones having …
Read More »What is proton therapy?
All matter consists of atoms and all atoms have protons along with other subatomic particles. When an accelerated beam of proton is incident on the target tissue like a tumour, due to their relatively enormous size, protons scatter less easily in the tissue and there is very little lateral dispersion. Therefore, the beam stays focused on the tumour shape without …
Read More »What is presbyopia? Which lens is used to correct it?
An eye that suffers from myopia as well as from hypermetropia is said to suffer from presbyopia. A person with this defect cannot see objects distinctly placed at any distance from him. To correct this defect, a person is prescribed bifocal lens that has both types of lenses — convex and concave.
Read More »What is polygraphy?
This is the process of using an instrument called polygraph, which is also popularly known as a lie detector.
Read More »What is Pluto – a Star or a Comet?
Which is the planet farthest from the sun? Pluto, of course. But, some recent findings suggest that Pluto is not a planet at all. It seems Pluto could actually be a comet, reports the National Geographic website. Basically, it is Pluto’s small size that has got it into trouble. It has a diameter of approximately 1,420 miles or 2,280 kilometers. …
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