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Why resistivity of semiconductors decreases with temperature?

The solid materials having properties in between conductors and insulators are known as semiconductors. A semiconductor is a material which is neither a good conductor nor good insulator of electricity.Its resistivity lies in between conductors and insulators,which is 100 Ω cm.The energy gap between conduction and valence band is narrow for semiconductors with respect to insulators. With the rise in temperature ...

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Why does n-type semiconductors have so many electrons than holes?

The elements of group V are pentavalent such as arsenic (As) ,phosphorus (P),bismuth (Bi),and antimony (Sb).These have five electrons in their valence band.When one of these materials is added to semiconductor like Si,four of its valence electrons from four covalent bonds with neighboring Si atoms and the fifth electron becomes free.The numbers of free electrons is equal to the numbers ...

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In our body,are there more neutrons than protons?

Human body mainly contains water nearly 70 %.In all neutral atoms,the number of protons and electrons are equal.If you did have many more protons or electrons,yous body would become electrically charged,but normally ,the amount of protons and electrons are the same. Of course the human body contains many different elements,and some of these are of high atomic number.On the other ...

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What is difference between Electrostatic force and nuclear force

Electrostatic force: Electrostatic force acts between charged particles only. Electrostatic force is a long range force. A proton can interact with all the protons within the nucleus through electrostatic force. Electrostatic force is a weak force. Nuclear force: Nuclear force acts between the nucleons and it is independent of the charge. Nuclear force is short range force. A nuleon can ...

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Why are some lines in the hydrogen spectrum brighter than others?

In hydrogen spectrum,some spectral lines are brighter than others depending upon their energy level.These bright lines show that electrons have jumped from higher energy level to lower energy level.When electron jumps from some higher orbit,the energy released in the from of photon will be greater,and we get a brighter line.Thus in hydrogen spectrum some lines are brighter than others.

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Is an electron a particle or a wave?

In 1924,de Broglie proposed that particle acts as a wave and wave acts as a particle. Davisson and Germer experimentally confirmed the wave nature of electron.They showed that electrons are diffracted from metallic crystal in the same manner as x-rays and other wave.Hence electrons show wave like properties.J.J Thomson while measuring e/m of electron showed that electron is a particle.Thus ...

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Why is wave nature of matter not more apparent in our daily observations?

Since,the de-Broglie wavelength is given by the relation λ = h/mv As the value of Plank’s constant is very small,so the wavelength associated with ordinary object is so small and is difficult to observe.In our daily observations we deal with the objects having larger mass and smaller velocity,that is why the wave nature of such objects is not more apparent ...

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What is difference between photon and electron

Photon: A photon has no rest mass because it cannot be at rest with respect to an observer. A photon moves with the velocity of light. A photon is charge less particle. Momentum of the photon with frequency ν is: P=hν/c Electron: An electron has mass and may be at rest. An electron cannot move the velocity of light. An electron ...

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Does a photon have a de Broglie wavelength?

Yes a photon has de Broglie wavelength.In 1924,Louis de Broglie proposed that a particle must also act like wave,in silmilar way,wave behave like particles. In de Broglie hypothesis an electromagnetic wave is the de-Broglie wave for a photon moving with speed c.According to de-Broglie ,the wavelength of the photon is given by the relation: λ = h/p Where P is ...

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Properties and applications of x rays

What are X rays ? X-rays are the electromagnetic waves which are emitted by the atoms of those metals which have large atomic number,large number of protons in their nuclei so that the pull of the nuclei on their electrons is very large.When an electron of K or L shell of such an atom is displaced from these shells to ...

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