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Acceleration due to gravity formula and problems

What is gravitational acceleration? Acceleration of a freely falling bodies is called gravitational acceleration.The value of gravitational acceleration is 10 ms-¬≤.   Why value of g varies with altitude? Above formula shows that the value of acceleration due to gravity g depends on the radius of the earth at its surface.The value of g is inversely ¬†proportional to the square ...

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What is the law of conservation of enegy

What does law of conservation of energy mean? According to law of conservation of energy:”Energy can neither be created nor is it destroyed.It can only be transformed from one form to another.A loss in one form of energy is accompanied by an equal increase in the other forms of energy.The total energy remains constant.” According to Einstein’s mass energy relation: ...

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Heisenberg Uncertainity Principle

Heisenberg’s Uncertainity principle: When we are studying a large moving objects say a planet, then we can follow its definite path on which it travels. If we know its initial position and momentum, then we can predict its position and momentum at any other time. But this is not possible for electron, proton and neutron which are microscopic particles. Heisenberg ...

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alpha beta and gamma radiation

Discovery of Radioactivity: In the March 1896 Henri Becquerel announced the discovery of radioactivity similar to X-rays.Although rays (X-rays) had been discovered less than four month earlier it was already known that X-rays come from the fluorescence wall of the discharge tube and thus it was thought that fluorescence and phosphorescence might be responsible for them. Becquerel known that Uranium ...

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What is quantization of energy

Quantization of energy: The assumptions made by Plank in deriving his radiation law and their consequences along with significance of Plank’s constant h were not immediately clear to his contemporaries and even to Plank himself.Plank derived his radiation law by analyzing the interaction between radiation in the cavity volume and the atoms of the cavity walls.He assumed that these atoms ...

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What is thermal radiation

Thermal radiation: Radiation emitted by such a body due to its temperature is called thermal radiation.All bodies not only emit such radiation but also absorb it from their surroundings.If the rate of absorption and emission from a body become equal ,the body is said to be in thermal equilibrium with its surroundings. The spectrum of thermal radiation from a hot ...

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Can a transformer operate on DC?

A transformer cannot operate on a steady or unchanging dc voltage such as that of a battery.It requires a voltage which rises and falls.Since an ac voltage not only changes its magnitude but its direction as well,it is used to operate the transformers. However,a transformer will operate from dc voltage if this voltage also undergoes changes.Transformers used for audio amplifiers ...

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What is Photovoltaic effect

Photovoltaic effect: An effect arising when a junction exists between two dissimilar materials and one of the materials is exposed to electromagnetic radiation,usually in the range near ultraviolet to infrared.The two materials may,for example,be a metal and a semiconductor or two semiconductors of opposite polarity,the combination forming a Schottky barrier and a P-N junction respectively.A forward voltage appears across the ...

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What instrument is used to measure atmospheric pressure?

Barometer is an instrument used to measure atmospheric pressure. How can we measure atmospheric pressure by mercury barometer? Mercury barometers consist of a glass tube about 80 cm long,closed at one end.The tube is filled with mercury and then placed,open end downward,in a reservoir of mercury.As the atmospheric pressure changes ,the level of the mercury changes and to a lesser ...

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Impedance and reactance

Circuits with capacitors and inductors are more complicated than the resistive circuits we talked about earlier ,in that their behavior depends on frequency:A “voltage divider ” containing a capacitor or inductor will have a frequency dependent division ratio.In addition ,circuits containing these components (known collectively as reactive components),”corrupt” input waveforms such as square waves,as we just saw. However,both capacitors and ...

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