Atomic Structure Questions and Answers

In Bohr s model of the hydrogen atom which of the following statement is incorrect Tagsfag f A The radius of the nth orbit is proportional to n nth B The total energy of the electron in nth orbit is inversely proportional to n he 3 f th Fri C The angular momentum of electron in an nth orbit is an integral multiple of h 27 D The magnitude of potential energy of the electron in any orbit is greater than its kinetic for deg a al fefde Gu fu Your Answer qu R

Two bubbles coalesce to form a single bubble If V is the subsequent change in the volume of contained air and S the change in total surface area T is the surface tension and P atmospheric pressure which of the following relation is correct assume temperature is constant 1 4PV 3ST 0 2 3PV 4ST 0 2014 3 2PV 3ST 0 4 3PV 2ST 0

48 Sodium has body centred packing Distance between two nearest atoms is 3 7 The lattice parameter is a 6 8 c 3 0 9 A block of mass M is attached to the lower end b 4 3 d 8 6 corsant value k The eleased from rest with the spring hod The maximum extension ceiling and has mes or muita mas

37 Magnetic field at the centre of nucleus of the hydrogen like atoms atomic number Z due to the motion of electron in nth orbit is proportional to 73 b na Z LAY ZS a 25 Z 73 c

Given below are densities of some solids and liquids Give rough estimates of the size of their atoms Substance Carbon diamond Gold Nitrogen liquid Lithium Fluorine liquid Atomic Mass u 12 01 197 00 14 01 6 94 19 00 Density 10 Kg m 2 22 19 32 1 00 0 53 1 14 Hint Assume the atoms to be tightly packed in a solid or liquid phase and use the known value of Avogadro s number You should however not take the actual numbers you obtain for various atomic sizes too literally Because of the crudeness of the tight packing approximation the results only indicate that atomic sizes are in the range of a few

17 The allowed orbits for electron are those in which Electron does not radiate energy Electron radiate energy b c d Orbits are circular Orbits are spiral

A moving neutron collides with a singly ionized stationary helium atom that is in ground state What should be the minimum speed of the moving neutron for the collision to be perfectly inelastic a 2 50 x 104 m s c 6 25 x 104 m s b 4 25 x 104 m s d 9 89 x 104 m s

Bohr model is applied to singly ionized helium He Consider the lines that lie in the visible region of the spectrum Which of the following transitions can give a photon of visible light Het fa fa fe Aur di Pulafe OPTIONS MARK FOR REVIEW CLEAR SELECTION A B n 5 ton 4 n 5n 4 4 n 7 to n 4 n 7n 4 n 219 n 1

RADIUS TE PE KE OF H HYDROGEN LIKE ATOMS BOHR S ATOMIC MODEL JUMPING OF e An electron in the hydrogen atom jumps fr excited state to the ground state The wavelength emitted illuminates a photosensitive material hav work function 2 75 eV If the stopping po the photoelectron is 10 V then the value a 2 b 3 d 5

explain the highlighted part why curve for electron and a staight line for PROTON EXP LAIN ME THE REASON FOR THIS IN THE GRAPH OF QUESTI ON Given below are three schematic graphs of potential energy V r versus distance r for three atomic particles electron e proton p and neutron n in the presence of a nucleus at the origin O The radius of the nucleus is ro The scale on the V axis may not be the same for all figures The correct pairing of each graph with the corresponding atomic particle is KVPY SB SX 2011 1 2 1 1 n 2 p 3 e 2 1 p 2 e 3 n 3 1 e 2 p 3 n V 3 Mak

For a certain hypothetical one electron atom the wavelength in A for the spectral lines for transitions originating at n P and terminating at 1 are given by where P 2 3 4 Take hc 1240 1500P P 1 eV nm Find the wavelength of most energetic photons in series In nm The first excitation potential of the atom is Nx102 eV Find value of N

What is the correct equation for the solubility product when calcium phosphate is dissolved in water A Ksp Ca2 PO4 B Ksp 3Ca2 2PO4 C Ksp Ca PO4 D Kp Ca2 3 PO4 1 E Ksp 3Ca 1 2PO43 1

SolveLancer Test An electron is revolving in an nth orbit of radius r with velocity v Now if the radius is increased by 16 times of original and electron s position is changed then velocity is changed by 4 times Then what is the location of electron now SolveLancer Test a 4n b 4 n c n 4 d n

The work function of a photosensitive surface is 3 2 eV The wavele of the incident radiation for which the stopping potential is 3 V lies in th O Visible region O IR region OUV region O Radiowave region

A proton is fired from very far away towards a nucleus with charge Q 120e where e is the electronic charge It makes a closest approach of 10 fim to the nucleus The de Broglie wavelength in units of fm of the proton at its start is take the proton mass m 10 7 kg 4 2 x 10 5 10 5 m 41080 9 10 1 fm

A photon creates a pair of electron positron with equal kinetic energy Let kinetic energy of each particle is 0 29 MeV Then what should be energy of the photon MP PET 2008 a 1 60 MeV c 2 0 MeV b 1 63 MeV d 1 90 MeV

i The mass of a particle moving with velocity 5 x 106 m s has de Broglie wavelength associated with it to be 0 135 nm Calculate its mass i In which electromagnetic wavelength lie region of the spectrum does this All India 2011C

An electron initially at rest falls through a potential difference of 16 V The De Broglie wavelength of the electron is nearl A 0 3 A B 3 A C 0 03 A 4

Q1 The radius of a Cu nucleus is measured to be 4 8 10 3 cm A The radius of a Mg nucleus can be estimated to be a 2 86 x 10 3 cm b 5 2x 10 3 cm Ans c c 3 6x 10 3 cm d 8 6x 10 3 cm

i In hydrogen atom an electron undergoes transition from second excited state to the first excited state and then to the ground state Identify the spectral series to which these transitions belong 1 Find out the ratio of the wavelengths of the emitted radiations in the two cases

Calculate the three lowest energy levels in eV for an electron inside a one dimensional infinite potential well of width 2 Also determine the corresponding normalized eigenfunctions Given mass of electron 31 34 19 m 9 1 x 10 kg h 1 05 x 10 Js 1 eV 1 6 10 J

An electron with speed v and a photon with speed c have the same de Broglie wavelength If the kinetic energy and momentum of electrons is E and P and that of photon is Eph and Pph respectively the correct option is Ee 2c V 1 E ph P D e 2c E 2 E 4 ph P D e 8 12 2c V

A 12 5 eV electron beam is used to bombard gaseous hydrogen at room temperature Upto which energy level the hydrogen atoms would be excited Calculate the wavelengths of the first members of Lyman and first member of Balmer series

A doubly ionised lithium atom is hydrogen like atom with atomic number 3 The wavelength of radiations required to excite that electron from first to third orbit is nearly O 912 O 416 2 O 307 O 114

A resistor and an 26 In a photocell circuit the stopping potential Vo is a measure of the maximum kinetic energy of the photoelectrons The following graph shows experimentally measured values of stopping potential versus frequency v of incident light V V 5 4 5 3 2 0 4 0 8 1 2 1 6 2 v 10 Hz The values of Plank s constant and the work function as determined from the graph are taking the magnitude of electronic charge to be e 1 6 x 10 19 C

The energy of a hydrogen atom in the ground state is 13 6 eV The energy of a He ion in the first excited state will be 2010 a 13 6 eV c 54 4 eV b 27 2 eV d 6 8 eV

A particle having zero rest mass and non zero energy and momentum must travel with a speed a equal to c the speed of light in vacuum b tending to infinity c greater than c d less than c

When an electron in hydrogen like atom jumps from a higher energy level to lower energy level O Angular momentum of the electron remains constant O Kinetic energy of electron decreases O Wavelength of de Broblie wave associated with motion of the electron decreases O Potential energy of the electron increases

s it in the syllabus of neet 69 Nuclear Fission is best explained by Liquid drop model 2 Yukawa meson theory 3 Independent particle model of the nucleus 4 Proton proton cycle

An election from various excited states of hydrogen atom emits radiation to come to the ground state Let A Ag be the de Broglie wavelength of the electron in the nth state and the ground state respectively Let A be the wavelength of the emitted photon in transition from the nth state to the ground state For large n A B are constants JEE Main 2018 a 2 c B 22 b A 2 d A 2n

es up 44 Three semi conductors are arranged in the increasing order of their energy gap as follows The correct arrangement is 1 Tellurium germanium silicon 2 Tellurium silicon germanium 3 Silicon germanium tellurium 4 Silicon tellurium germanium

An a particle of 5 MeV energy collides with a nucleus of uranium Z 92 at rest at a scattering angle of 180 The nearest distance upto which a particle reaches the nucleus will be of the order of O 10 m O 10 11 cm 10 15 cm 10 12 m

Monochromatic light of frequency 6 0 10 4 Hz is produced by a laser The power emitted is 2 x 10 w The number of photons emitted on the average by the sources per second is a 5 1016 c 5 1014 2007 b 5 1017 d 5 1015

Q No 15 One mole of an ideal monoatomic gas at temperature To expands slowly according to the law gas is 1 2 3 Correct Answer 1 Your Answer 3 Status incorrect 2RTO RTO 3 RTO RTO 2 View In English constant If the final temperature is 2To heat supplied to the 4

In a sample of hydrogen like atoms all of which are in ground state a photon beam containing photons of various energies of a band spectrum consisting of a single wide band spanning visible and UV part of electromagnetic spectrum is passed In absorption spectrum five dark lines are observed The number of bright lines in the emission spectrum will be assume that all transitions take place

Which of the following is correct Question Type Single Correct Type 1 Lyman series is a continuous spectrum 2 3 Paschen series is a line spectrum in the infrared Balmer series is a line spectrum in the ultraviolet The spectral series formula can be deriv

Consider a hydrogen like atom whose energy in nth excited state is given by 13 6 2 En when this excited atom makes a transition from an excited state to ground state The most energetic photons have energy Emax 52 224 eV and the least energetic photons have energy Emin 1 224 eV tom Find n Z

The energy of a photon of sodium light 589 nm equals the band gap of a semiconducting material a Find the minimum energy E required to create a hole electron pair b Find the value of E kT at a temperature of 300 K

7 An electron microscope is used to look at an atom of 1 0 A diameter We desire a resoltuion of about 0 05 A The minimum energy of electron should be 6 0 x 104 eV a 0 957 eV c 10 x 104 eV b d 1 24 KeV

The ground state energy of hydrogen atom is 13 6 eV If the electron jumps to the ground state from the 3rd excited state the wavelength of the emitted photon is A B C D 875 A 1052 A 752 A 974 A Correct Answer

circuit 1 the potential is the same everywhere 2 the p type side is at a higher potential than the n type side itonital 3 there is an electric field at the junction directed from the n type side to the p type side 4 there is an electric field at the junction directed

Which level of the single ionized carbon hasothongo the same energy as the ground state energy of hydrogen atom mat thongo 1 1 2 6 nathongo 3 4 mathongo 4 8 mathongo mathongo mathongamathongo mathongo mathongo ma mathongo mathongo ma mathongo mathongo ma mathongo

Graph shows a hypothetical speed distribution for a sample of N gas dN dN particle for V Voi is rate of change of number of particles dV dV 0 with change velocity A The value of aV is 2N B The ratio Vavg Vo is equal to 2 3 C The ratio Vrms V is equal to 1 2 D Three fourth of the total particle has a speed between 0 5 V and V a 212 2 ON speed V

54 Suppose the potential energy between electron and ke proton at a distance r is given by U 3x3 Assuming Bohr s Model to be valid for this atom if the speed of electron in nth orbit depends on the principal quantum number n as v n then find the value of x a 1 c 3 b 2 d 4

7 The shortest wavelength of the Bracket series of a hydrogen like atom atomic number 2 is the same as the shortest wavelength of the Balmar series of hydrogen atom The value of Z is a 2 b 3 c 4 d 6 the

Identify the incorrect statements a An electronic wave function must be symmetrical with respect to the interchange of any two electrons b y must remain unchanged when the spin and space coordinates of the paired electrons are interchanged c For an n electron system the wave function y will be a function of 3 n spatial coordinate d Antisymmetrical wave function are found to represent the properties of electron

5 The maximum kinetic energy of an electron is E when the incident wavelength is To increase the maximum kinetic energy of the electron to 2E the incident wavelength must be a 22 b 2 2 d hc EN hc hc EX hc

avelength of matter waves is also determined by using kinetic energy as formula is h 2mE If you double the kinetic energy of a particle how does the deBroglie wavelength change OPTIONS A 2 1 707 A 1 A 2 0 707 A 1 A 2 1 5 A 1

PASSAGE Wavelength of matter waves is also determined by using kinetic energy as formula is h 2mE Choose the correct options Marks 2 The kinetic energy of an electron is 5 eV Calculate the de broglie wavelength associated with it h 6 6 x 10 34 Js m 9 1 x 10 31 kg OPTIONS 5 47 A 10 9 A

Consider a hypothetical atom having atomic number z 2 It has two electrons each having mass m Assume that both electrons always lie diametrically opposite and nucleus of atom contains two proton Assume Bohr model is applicable Find the radius of first orbit of this atom upto one h decimal place in pm given 1 65 A me