Atomic Structure Questions and Answers

If the energy difference between the ground state of an atom and excited state is 4 4 x 10 19 J The wave length of photon required to produce this transition is 1 4 5 x 10 7 m 3 4 5 x 10 7 2 4 5 x 10 7 nm 4 4 5 x 10 7 cm

The ratio of angular speed and tangential speed of electron in nth orbit of hydrogen atom is NCERT Pg 425 1 Inversely proportional to n 2 Directly proportional to n 3 Inversely proportional to n Independent of n

An electron in a hydrogen atom makes a transition from n to n If the time period of electron in the initial state is eight times that in the final state then 1 n 3n 3 n 2n 2 n 4n 4 n 5n

The impulse imparted by an electromagnetic pulse of energy 1 5 x 10 2 joule when it falls normally on a perfectly reflecting surface is Only one correct answer A B C D 4 10 10 kg m s 2x10 10 kg m s 10 10 kg m s 0 5 10 10 kg m s

Whenever a photon is emitted by hydrogen atom in Balmer series it is followed by another photon in Lyman series What wavelength does this later photon corresponds to a 103 nm c 91 3 nm b 122 nm d It can have any value

Ionisation potential of hydrogen atom is 13 6 eV Hydrogen atoms in the ground state are excited by monochromatic radiation of photon energy 12 1 eV According to Bohr s theory the spectral lines emitted by hydrogen will be 1 two 2 three 3 four 4 one

A hydrogen atom is in an excited state of principle quantum number n em ts a photon of wavelength A when it returns to the ground state The value of n is 1 R VR 1 OXR 1 ORR 1 OR 1 7 R

NEET PHYSICS Q 70 The product of angular speed and tangential Q 70 speed of electron in n orbit of hydrogen atom is 1 Inversely proportional to n 2 Directly proportional to n 3 Inversely proportional to n 4 Independent of n All India Major Test Series Phase l II Major Test 38 32 01 08 2020 of 1 2 n 3 na h 4 n LTD www

wavelength of radiation emitted when the electron jumps from the excited state to the ground state is nearly 1 Rydberg is equal to RH O 303 O 202 O 103 O 405

The energy of an electron in an excited hydrogen atom is 3 4 eV The angular momentum of the electron in this state according to Bohr s theory is nearly 02 1 x 10 34 Js 0 4 2 x 10 34 Js 1 1 x 10 34 Js 03 1 10 34 Js

12 Review What is the value of the de Broglie wavelength of an electron when it is accelerated from rest through a potential difference of 150 V Only one correct answer

11 Review An electron in a hydrogen atom makes a transition from n N to n N The frequency of the electron in the final state is eight times that in initial state The possible values of N and N are Only one correct answer

The energy of an electron in the ground state of a hydrogen atom is 13 6 eV Suppose there is an electron in the first excited state n 2 It emits a photon and goes to the ground state The energy of the emitted photon is A 17 0 eV B 13 6 eV C 10 2 eV D 3 4 eV

Q No 1 View In English A source S is producing 1015 photons per second of wavelength 5000 A Another source S2 is producing 102 x 1015 photons per second of wavelength 5100 A Thon power of 52 power of 5 equal to 1 2 3 4 Correct Answer 2 Status unattempted 0 98 100 1 02 1 04 Add to Bookmark List

The recoil speed of a hydrogen atom after it emits a photon in going from n 5 state to n 1 state will b 1 4 17 m s mathongo mathongo mathongo mathongo mathongo 2 4 34 m s 3 219 m sngo mathongo mathongo mathongo mathongo 4 3 25 m s

Calculate the energy difference between two energy levels if an electron jumps from 2nd excited state to 5th excited state and the length of the box is 0 760 nm a 1 05 eV b 13 7 eV c 2 22 eV d 17 6 eV

1 a potential mo r2 where r is the distance from the origin Applying the Bohr model in this case the radius of the particle in its nth orbit in term of a h 2amo is a a n c an b an d an n

rogen anion using the Bohr model we assume that its two electrons move in an orbit such that they are always on diametrically opposite sides of the nucleus With each electron having the angular momentum h 2 and taking electron interaction into account the radius of the orbit in terms of the Bohr radius of hydrogen atom a a a c 2 3 a B b aB 3 d aB 2 4 h 2 me is

H 21 The magnitude of acceleration of the electron in the nth orbit of hydrogen atom is a and that of singly ionized helium atom is The ratio a a He a is He a 1 8 V c 1 2 b 1 4 d dependent on n

42 If potential energy of electron in ground state is considered to be zero in hydrogen atom Total energy of electron in second excited state is 1 1 5 eV 2 12 1 eV 3 24 2 eV 4 25 7 eV 3 Density of nucleus is of the order of 1 106 kg m C

Consider the ion Be treat it as a hydrogen like atom within the Bohr model having 4 protons and 5 neutrons a What is the ground state energy of the Be ion b What is the wavelength of a photon that can excite Be to the n 3 state c In the absence of any external field What is the longest wavelength that the excited ion might emit d If a strong magnetic field is applied while the atom is in its n 3 state what is the shortest wavelength of a photon that the atom can emit as its electron transitions from the 3d 1 2 to the 2p 1 1 orbital Ignore spin contributions if you wish

40 19K converts to 18 Ar by positive B decay as well as electron capture Let Q values for the decay and electron capture be Q and Q respectively in the above reaction A Q Q B Q Q C neutrino emitted in positive decay is monoenergetic D neutrino emitted in electron capture is monoenergetic

In NPN transistor 1010 electrons enter in emitter region in10 6 s If 2 electrons are lost in base region then collector current and current amplification factor B respectively are Question Type Single Correct Type 1 1 57 mA 49 2 1 92 mA 70 3 2 mA 25

3 The ratio of magnetic dipole moment and angular momentum of the electron in a Li ion is 1 Proportional to the quantum number n 2 Half the specific charge of an electron 3 Proportional to n n is the quantum number 4 Twice the specific charge of an electron

The electron is present in the 1 51 eV energy state for H atom The radius of orbit of electron in this orbit is about 0 53 2 38 1 59 4 77

In the diagram shown below two atomic transitions are shown If X 4000 and 500 nm then A will be nearly 444 nm 900 nm 222 nm 600 nm

hr mi The ratio of the wavelength of first line of Lyman series ar first line of Paschen series is 5 27

hr min The ratio of the wavelength of first line of Lyman series and first line of Paschen series is 5 27

Question No 30 The difference between n 1 th Bohr radius and nth Bohr radius is equal to the n 1 th Bohr radius The value of n is O 1 02 03

If the scattering intensity of a liquid is 8 units at a wavelength of 500 nm then the scattering intensity at a wavelength of 400 nm will be approximately A B C D 13 units 16 units 20 units 24 units SiTy X M

than 90 is RT Pg 416 ested that 7 An electron in a hydrogen atom makes a transition from n n to n n The time period of revolution of the electron in the initial state is eight times that in final state The possible value of n and m2 are 1 m 4 n 3 n 8 n 1 9 2 NCERT Pg 429 2 n 8 n 2 4 n 6 n 2 tom is an atom in which

A hydrogen atom initially in the ground state absorbs a photon and is excited to n 4 level then the wavelength of photon is nearly INCERT Pg 427 790 A 2 870 A 3 970 A 4 1070 A

13 lonization potential of hydrogen atom is 13 6 eV Hydrogen atoms in the ground state are excited by monochromatic radiation of photon energy 12 1 eV According to Bohr s theory the spectral lines emitted by hydrogen will be NCERT Pg 429 1 One 2 Two 3 Three 4 Five

A cathode ray oscilloscope CRO is a device which convertes electrical signals into an active graphical representation on a fluorescent screen The x axis is always time axis where the 1 cm is equal to a preset time scale called time base A sound wave is displayed on the screen of a cathode ray oscilloscope The time base of the CRO is set at 2 5 millisecond per cm Voltage the frequency of the sound wave is Hz 1cm Time

The radionuclide 1 C dacays by B emission Write symbolically this decay process Given that Calculate the Q value m C 11 011434 u m 1 B 11 009305 u m 0 000548 u lu 931 5 MeV c AIPMT 2

An electromagnetic radiation whose electric component varies with time as E Eo 1 coswt cos wot w 6 x 10 5 rad s wo 2 8 x 10 4 rad s is incident on a lithium surface work function 2 39 eV The maximum kinetic energy of a photoelectron liberated from the lithium surface is h 4 14 xx10 15 eV s

The ionisation energy of a hydrogen like Bohr atom is 4 Rydbergs The wavelength of radiation emitted when the electron jumps from the first excited state to the ground state is nearly 1 Rydberg is equal to RhC O 303 O 202 O 103 O 405

An electron in a hydrogen atom makes a transition from n N to n N The frequency of the electron in the final state is eight times that in initial state The possible values of N and N are Only one correct answer A B 6 2 D N 8 1 C N 8 2 N 4 N 2 i

What is the value of the de Broglie wavelength of an electron when it is accelerated from rest through a potential difference of 150 V Only one correct answer A 0 5 B 1 0 A C 1 5 A

An electron is moving with an initial velocity v v i and is in a magnetic field B B j Then it s de Broglie wavelength 1 remains constant B B j 2 increases with time 3 decreases with time 4 increases and decreases periodically e B Boj V V

2 In a hydrogen atom if the potential energy of first excited state is taken as reference zero potential energy then total energy of ground state will be written as 2 6 8 eV 4 13 6 eV 1 6 8 eV 3 13 6 eV

In alpha particle scattering experiment the perpendicular distance b of initial velocity vector of the a particle from the centre of nucleus is equal to where E is initial kinetic energy of a particle 2e Ze sin 4 E Ze cot 48 E 8 8 Nucleus Ze

The de Broglie wavelength of the electron in the ground state of the hydrogen atom is radius of the first orbit of hydrogen atom 0 53 1 1 67 3 1 06 2 3 33 4 0 53

An electron is accelerated through a potential 50 difference of 10000 V The de Broglie wavelength of the electron is 1 0 123 3 0 186 2 0 356 4 0 258 far 1 0 123 A 3 0 186 A 10000 V fa at caf 2 0 356 A 4 0 258 A

14 Two unpaired electrons present in carbon atom are different with respect to their A Principle quantum number B Azimuthul quantum number D Spin quantum number C Magnetic quantum number 15 Number of electron having the quantum numbers n 4 f 0 5 in Zn ion is are A 1 B 0 C 2 D 5 16 Spin angular momentum for unpaired electron in sodium Atomic No 11 3 h B 0 866 h 2 C A D None of these

Directions In the following question a statement of assertion A is followed by a statement of reason R Mark the correct choice as a If both assertion and reason are true and reason is the correct explanation of assertion b If both assertion and reason are true but reason is not the correct explanation of assertion c If assertion is true but reason is false d If both assertion and reason are false 32 Assertion Balmer series lies in the visible region of electromagnetic spectrum Reason 1 R 1 22 1 2 1 where n 3 4 5

Choose CORRECT statement A Electron proton which are accelerated through same potential difference from rest will have same de broglie 5 8 4 PORT AND FIE wavelength 24e4 B Proton and a particle which are accelerated through same potential difference from rest will have same de broglie wavelength HODIFA C Two particles having same kinetic energy DETS must have same de broglie wavelength D Two particles having having different momentum may have same de broglie

4 tan 1 1 3 3 IN 37 A hydrogen like atom of atomic number z is in an excited state of quantum number 2n It can emit a photon of maximum energy 204 eV If it makes a transition in quantum state n a photon of energy 40 8 eV is emitted the value of n will be 2 2 4 4 2

A hydrogen atom and Li ion are both in th econd excited state If L and L are the espective electronic angular momenta and E and E their respective energies then 1 L L and E E and E E 2 L L 3 L L and E E 4 L L and E E

In a hypothetical system a particle of ma and charge 3q is moving around a heavy particle charge q Assume that E model is applicable to this system then vel of mass m in first orbit is 1 3q 26 h 3q 2 h 2 4 3q 4sh 3q 4 h