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question_answer1) What is the wavelength (in nm) of the radiation emitted when the electron in a H-atom jumps from \[n=\infty \] to\[n=2\]?
question_answer2) Find the binding energy (in ev) of a H-atom in the state \[n=2\]-
question_answer3) Calculate the value (in volt) of the first excitation potential of \[H{{e}^{+}}\]ion.
question_answer4) If Bohr?s Theory is applicable to \[_{100}F{{m}^{257}}\]then radius of 5th orbit in Bohr?s unit is?
question_answer5) Radiations of wavelength\[\lambda \]are incident on hydrogen in the ground state. A fraction of these radiations absorbed by these atoms. There are ten different waves in the emission spectrum of excited atoms. Find the value of\[\lambda \]. (in nm)
question_answer6) As per Bohr model, the minimum energy (in eV) required to remove an electron from the ground state of doubly ionized Li atom \[(Z=3)?\]
question_answer7) Through what potential difference should an electron be accelerated so that its de Broglie wavelength become \[0.4{\AA}\](in volt)
question_answer8) The study of diffraction of electrons from a target, gives the wavelength associated as\[0.65{\AA}\].The energy (in eV) of the electrons will be?
question_answer9) The radius of the second orbit of an electron in hydrogen atom is\[2.116{\AA}\]. The de-Broglie wavelength associated with this electron in this orbit would be \[(in{\AA})?\]
question_answer10) The ratio of the magnetic dipole moment to the angular momentum \[(L=mvr)\] is a universal constant for hydrogen-like atoms and ions. Its value is\[a\times 2.2\times {{10}^{10}}C/kg\]. Find the value of a.
question_answer11) Electrons are emitted from an electron gun at almost zero velocity and are accelerated by an electric field E through a distance of 1.0 m. The electrons are now scattered by an atomic hydrogen sample in the ground state. What should be the minimum value of E so that red light of wavelength \[656.3nm\]may be emitted by the hydrogen? If its value is\[a\times 6.05eV\]. Find the value of a.
question_answer12) Two neutral particles are kept 1 m apart. Suppose by some mechanism some charge is transferred from one particle to the other and the electric potential energy lost is completely converted into a photon. Calculate the longest wavelength (in m) of the photon possible.
question_answer13) An electron and a proton are separated by a large distance and the electron approaches the protons with a kinetic energy of 4.11 eV. If the electron in captured by the proton to form hydrogen atom in the ground state, the wavelength of photon given off is\[a\times {{10}^{2}}{\AA}\]? Find the value of a.
question_answer14) A neutron beam, in which each neutron has same kinetic energy, is passed through a sample of hydrogen like gas (but not hydrogen) in ground state. Due to collision of neutrons with the ions of the gas, ions are excited and then they emit photons. Six spectral lines are obtained in which one of the lines is of wavelength\[\text{(}6200/51\text{)}nm\]. What is the minimum possible value of kinetic energy of the neutrons for this to be possible. The mass of neutron and proton can be assumed to be nearly same. Give answer in the form \[25a\times {{10}^{-2eV}}\]and find value of a.
question_answer15) A gas of identical hydrogen like atoms has some atoms in the lowest (ground) energy level A & some atoms in a particular upper (excited) energy level B & there are no atoms in any other energy level. The atoms of the gas make transition to a higher energy level by the absorbing monochromatic light of photon energy\[2.55\text{ }eV\]. Subsequently, the atoms emit radiation of only six different photon energies. Some of the emitted photons have energy\[2.55\text{ }eV\]. Some have energy more some have less than\[2.55\text{ }eV\]. Find the principle quantum number of the initially excited level B.
question_answer16) A \[H{{e}^{+}}\]ion in ground state in fired towards a hydrogen atom in ground state and at rest. What should be the minimum kinetic energy (in eV) of \[H{{e}^{+}}\]ion so that both single electron species may get excited.
question_answer17) Determine the number of lines in Paschen series which have a wavelength greater than 1000 nm.
question_answer18) Consider a universe in which the \[\pi \]-meson orbits around the nucleus instead of electron. Assuming a Bohr model for a \[\pi \]-meson of mass \[{{m}_{\pi }}\]and of the same charge as the electron is in a circular orbit of radius r about the nucleus with an orbital angular momentum\[\frac{h}{2\pi }\]. If the radius of a nucleus of atomic number Z is given by\[R=1.6\times {{10}^{-15}}{{Z}^{1/3}}m\]. The total number of elements in this universe that can exist is given as ?N?. Find the value of\[\left[ \frac{N-1}{12} \right]\]. [Given \[\frac{{{\varepsilon }_{0}}{{h}^{2}}}{\pi {{m}_{e}}{{e}^{2}}}=0.53{\AA};\frac{{{m}_{\pi }}}{{{m}_{c}}}=265;\]neglect any shielding effect for the heavier atoms and assume non relativistic physics to be applicable and take \[{{5}^{1/4}}=1.5\]]
question_answer19) A potential difference of V volts is applied on two parallel electrodes separated by a distance of\[4.0\times {{10}^{-2}}m\]. The electrons of very low energy are injected into the region between the electrodes which contains argon at low pressure. The average distance the electrons travel between collisions with argon atoms is\[8\times {{10}^{-5}}m\]. The ionization energy of argon atom is\[16eV\]. Estimate the minimum value of V (in kV) such that the electrons will cause ionization in argon atoms by collision.
question_answer20) A neutron moving through container filled with stationary deuterons. The neutron successively collides elastically and head on with stationery deuterons one at a time. The mass of the neutron is equal to half that of the deuteron. How many such collision would be required to slow the neutron down from 81 eV to 1 eV. [Neglect the relativistic effect]
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