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CBSE Class 12-science Answered

Numerical Question
Asked by malhotravns | 24 Feb, 2010, 10:03: AM
answered-by-expert Expert Answer

Dear Student

Electron can not come out of metal sur face unless the incident energy is greater than or equal to 4.2 eV.

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Answered by | 01 Mar, 2010, 04:02: PM
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CBSE 12-science - Physics
The number of moles in an elemental sample is just the ratio of the mass m to atomic mass 4. n= A The number of protons N, in an elemental sample is Z (atomic number) times the number of moles of Avogadro's number NA N=ZnN P A Copper has an atomic mass of 63.5 g/mole and 29 protons per atom. If such an atom were neutral, then it would have as many protons as electrons. If you remove electrons from a neutral state, then you get a net positive charge. Given a 54 gram ball of copper with a net charge of 2.2 µC, what fraction of the copper's electrons have been removed?
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consider a hypothesis H-like atom, the wavelength in Amstrong for the spectral lines for the transition from n=p to n=1 is given as  wavelength =1500p^2/p^2 -1 where p>1 find the minimum and maximum wavelength
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A loop of irregular shape carrying current is located in an external magnetic field. If the wire is flexible, why does it change to a circular shape?
Asked by kbsahilsid18 | 13 Aug, 2020, 10:02: AM
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CBSE 12-science - Physics
Why emission spectra are seen in only those gases which have low density or low number of collisions?
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At stopping potential does the work function becomes zero?
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Asked by pardeepkumar2281 | 28 Feb, 2019, 07:24: PM
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CBSE 12-science - Physics
What is the order of velocity of an electron in H atom in ground state ?
Asked by pradeepjsme | 30 Jan, 2019, 03:54: PM
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CBSE 12-science - Physics
What is the order of velocity of an electron in a H-atom in ground state?
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