A light bulb gives off light because an electric current is passed through its filament,a thread of tungsten metal thinner than a human hair, which then becomes white hot. Sir Joseph Swan (1828-1914) in the England and Thomas Alva Edison (1847-1931) in the United States constructed the first incandescent electric lamps in 1879. They succeed in preventing the rapid burning …
Read More »Why does an automobile have a carburetor?
An automobile is driven by an internal combustion engine which will work properly only if the right amounts of petrol and air are mixed together. The carburetor is the part of the engine where the mixing takes place. The burning of fuel in the engine is a chemical reaction in which petrol combines with the oxygen of the air to …
Read More »शुभ मुहूर्त
एक समय की बात है – एक बहुत की भोला – भाला दम्पति था। पति – पत्नी, दोनों ही इतने ज्यादा भोले थे कि कई बार तो उनके निपट मूर्ख होने का भी संदेह होता था। एक रात में कुछ शोर सुनकर दोनों उठ बैठे। “मालूम होता है, घर में चोर घुस आए हैं,” आदमी फुसफुसाया। “क्यों भागवान, तुम्हे कुछ सुनाई …
Read More »Why does alternating current repel while direct current attract objects?
A winding (conductor) carrying direct current (DC) produces a magnetic field akin to a permanent magnet. The current carried by this conductor is unidirectional and steady i.e. it does not change direction or vary in magnitude with respect to time. Hence, the effect is that of a permanent magnet which simply attracts objects near the coil. The case is different …
Read More »Why does a volcano erupt?
By now you should be aware that in the bowels of the Earth all is not still. On the contrary, it is very active. One obvious example the the Earth’s internal working is the activity of volcanoes. There are many famous instances of a volcano erupting and spewing white hot, molten rock from it mouth; if you have been to …
Read More »Why does a magnet attract iron?
Magnets attract iron due to the influence of their magnetic field upon the iron. Before a piece of iron enters the magnetic field of a magnet, the polarization of the iron’s atoms is random. When exposed to the magnetic field, the atoms begin to align their electrons with the flow of the magnetic field, which makes the iron magnetized as …
Read More »Why does a hair-cut not hurt?
All our senses are controlled by our nerves, which carry their messages to the brain. Therefore, any part of us that has nerves also has a sense of feeling. We might fall and cut ourselves, or have a tooth that aches. We are made well aware of pain because the damaged parts contain nerves. Our hair, however, does not contain …
Read More »Orhan Pamuk
Orhan Pamuk — Ferit Orhan Pamuk was born on 7 June 1952, generally known simply as Orhan Pamuk, is a Turkish novelist. He is also the Robert Yik-Fong Tam Professor in the Humanities at Columbia University, where he teaches comparative literature and writing. One of Turkey’s most prominent novelists, his work has sold over seven million books in more than …
Read More »Why does a falling object have no weight?
Every body on this earth is attracted by the gravitational pull of the earth. A freely falling object has weight W=mg, where W-weight, m-mass of the object and g-acceleration produced due to the earth’s gravity. An object kept in a lift which falls freely, weighs zero on the weighing machine, but its actual weight is still mg. This happens because …
Read More »Why does a bull react violently to the colour red?
It is the movement of the cloth that makes the bull react violently as like most mammals, the bull too is colour blind and cannot be affected by the colour of the cloth. When a matador moves a cloth (irrespective of the colour) in front of the bull, it perceives the movement as a threat and is angered, and as …
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