Description : The amount of energy required to completely remove an electron from the first Bohr orbit is a) 13.6 MeV b) 13.6 eV c) 1.36 MeV d) 1.36 eV
Last Answer : b) 13.6 eV
Description : The total energy of electron in the Bohr orbit is given by the formula, E = a) - ke2 /2r b) - ke2 /2r2 c) - k 2 e/2r d) - ke2 /r
Last Answer : a) - ke2 /2r
Description : The quantized Bohr orbit radius of electron in hydrogen atom is given by a) n2 r3 b) nr1 c) n2 r2 d) n2 r1
Last Answer : d) n2 r1
Description : The value of first quantized Bohr orbit radius of hydrogen atom is a) 0.0053 nm b) 5.3 nm c) 0.053 nm d) 0.053 cm
Last Answer : c) 0.053 nm
Description : Calculate the radius of the first Bohr orbit of a `He^(+)` ion and the binding energy of its electron in the ground state.
Last Answer : Calculate the radius of the first Bohr orbit of a `He^(+)` ion and the binding energy of its electron in the ground state.
Description : Calculate the speed of the electron in the first Bohr orbit given that `h=6.6xx10^(-34) Js, m=9.11xx10^(-31) kg` and `e=1.603xx10^(-19) C`.
Last Answer : Calculate the speed of the electron in the first Bohr orbit given that `h=6.6xx10^(-34) Js, m=9.11xx10^(-31) kg` and `e=1.603xx10^(-19) C`.
Description : Which one of the following statements is WRONG? (A) A singlet or triplet state may result when one of the electrons from the HOMO is excited to higher energy levels (B) In an ... the electron from the singlet excited state returns to ground state, the molecule always shows fluorescence phenomenon
Last Answer : (C) Triplet excited state is more stable than the singlet excited state
Description : The de-Broglie wavelength of an electron moving in the nth Bohr orbit of radius ris given by
Last Answer : The de-Broglie wavelength of an electron moving in the nth Bohr orbit of radius ris given by A. `(2pir)/n` B. `npir` C. `(nr)/(2pi)` D. `(nr)/pi`
Description : The average current due to an electron orbiting the proton in the `n^(th)` Bohr orbit of the hydrogen atom is
Last Answer : The average current due to an electron orbiting the proton in the `n^(th)` Bohr orbit of the hydrogen atom ... `propn^3` C. `propb` D. none of these
Description : According to Bohr's theory, an electron in one Bohr stationary orbit can go to a higher stationary orbit (a) By emission of electromagnetic radiation (b) Without any absorption ... absorption of any electromagnetic radiation (d) With absorption of electromagnetic radiation of a particular frequency
Last Answer : Ans:(d)
Description : The speed of hydrogen electron in the nth orbit is given by vn = a) 2λke2 / nh b) 2πke2 / λh c) 2πke2 / nh d) 2πke2 / h
Last Answer : c) 2πke2
Description : The minimum energy required to eject an electron from a metal surface is called a) Intensity b) Threshold frequency c) Work function d) Photo energy
Last Answer : c) Work function
Description : An atomic energy state in which more atoms are in the lower energy state E1 than in the excited state E2, is known as a) population inversion b) normal population c) stimulated population d) atomic population
Last Answer : b) normal population
Description : Calculate the energy of hydrogen atom in the ground state given that the after Bohr orbit og hydrogen is `5xx10^(-11)m` and electronic charge is `1.6x
Last Answer : Calculate the energy of hydrogen atom in the ground state given that the after Bohr orbit og hydrogen is ` ... electronic charge is `1.6xx10^(-19) C`.
Description : For Hydrogen atom, the allowed stationary orbits are those whose orbital angular momentum is equal to an integral multiple of h i.e., mvr = a) nh/2π b) nh x 2π c) nh / 2λ d) nh / 2πλ
Last Answer : a) nh/2π
Description : Whichofthe followingantennasis best excited fromawaveguide? a. Biconical b.Horn c. Helical d. Discone
Last Answer : b.Horn
Description : In the phenomenon of Laser production, atom can reside in the excited state only for a) 10-6 s b) 10-7 s c) 10-8 s d) 10-9 s
Last Answer : c) 10-8 s
Description : The incident photon absorbed by an atom in the ground state E1, thereby leaving the atom in the excited state E2 , is a) spontaneous absorption b) stimulated absorption c) induced absorption d) both b & c
Last Answer : d) both b & c
Description : In order to obtain spectrum from the emitted radiation, the atomic gas or vapour must be excited at a) much less than atmospheric pressure b) much high than atmospheric pressure c) atmospheric pressure d) high pressure and temperature
Last Answer : a) much less than atmospheric pressure
Description : The energy required to excite an electron from the ground state of hydrogen atom to the first excited state, is
Last Answer : The energy required to excite an electron from the ground state of hydrogen atom to the first excited state, is A. ... 10.2 eV C. 0.85 eV D. 12.75eV
Description : A particle of mass `m` moves along a circular orbit in centrosymmetrical potential field `U(r )=kr^(2)//2`. Using the Bohr quantization condition, fin
Last Answer : A particle of mass `m` moves along a circular orbit in centrosymmetrical potential field `U(r ... orbital radii and energy levels to that particle.
Description : According to Bohr’s theory, the fourth stationary orbit of electrons in the hydrogen atom is a) 4 (0.053 nm) b) 9 (0.053 nm) c) 16 (0.053 nm) d) 25(0.053 nm)
Last Answer : c) 16 (0.053 nm)
Description : The electrons in the outermost orbit of atom are: a) Valance electrons b) Static electrons c) Tightly bound d) Stationary
Last Answer : a) Valance electrons
Description : If energy of incident photon is greater than the rest mass energy of electron positron pair, the surplus energy is shared by the pair as, a) Potential energy b) Thermal energy c) Electronic energy d) Kinetic energy
Last Answer : d) Kinetic energy
Description : The ionisation energy of hydrogen atom in the ground state is x KJ. The energy required for an electron to jump from 2nd orbit to 3rd orbit is?
Last Answer : 5x/36
Description : The energy released when an extra electron is added to a neutral gaseous atom is called (a) Bond energy (b) Electron affinity (c) Ionization potential (d) Electronegativity
Last Answer : Ans:(b)
Description : The collision between a photon and a free electron was first explained by which of the following scientists? w) Einstein x) Heisenberg y) Compton z) Bohr
Last Answer : ANSWER: Y -- COMPTON
Description : What electron would have the highest ionization energy for an oxygen atom?
Last Answer : What is the answer ?
Description : The alkali metals have (a) Low ionization energy (b) High electronegativities (c) High m.p. (d) Electron configuration of ns2np1
Last Answer : Ans:(a)
Description : Define the following : Atomic Radii , Ionization Energy , Electron Affinity , Electronegativity.
Last Answer : Ans :(1) Atomic Radii : An atom does not have strictly defined boundaries so it is impossible to determine the exact radius of an atom but theoretically it is defined as half the distance between the ... in Period : It increases from left to right in a period due to increase in nuclear charge.
Description : Electron are emitted from an electron gun at almost zero velocity and are accelerated by an electric field `E` through a distance of `1.0m` The electr
Last Answer : Electron are emitted from an electron gun at almost zero velocity and are accelerated by an electric field ... .5 nm` may be emitted by the hydrogen?
Description : How is the electron beam of a three-cavity klystron accelerated toward the drift tube?
Last Answer : A large negative pulse is applied to the cathode.
Description : Which of the following is characteristic feature of Le Fort II fracture Options: 1) The fracture line runs through the root of the nose, lacrimal bone, floor of orbit, upper part of maxillary ... ) Complete separation of the facial bones from the cranial bones 4) Isolated fracture of orbital floor
Last Answer : Correct Answer: 1) The fracture line runs through the root of the nose, lacrimal bone, floor of orbit, upper part of maxillary sinus and pterygoid plates
Description : If electron has to be confined in the nucleus, its speed would have to be greater than a) 1010 cm/s b) 1010 m/s c) 1020 m/s d) 1020 cm/s
Last Answer : b) 1010 m/s
Description : Electron can exist in the atom but outside the nucleus because a) speed of electron is equal to the speed of light b) speed of electron is more than speed of light c) speed of electron is less than speed of light d) None of these
Last Answer : c) speed of electron is less than speed of light
Description : A three dimensional image is obtained by a)Electron microscope b) Scanning electron microscope c) Magnetic imaging d)None of these
Last Answer : b) Scanning electron microscope
Description : The electron was discovered by a) Burcherer b) Anderson c) Chadwick d) J. J Thomson
Last Answer : d) J. J Thomson
Description : An electron moves with a velocity of 2 × 106 ms-1 in the direction of a uniform magnetic field of 0.8 Tesla. The force on electron is a) 8 N b) 2 N c) 4 N d) Zero
Last Answer : d) Zero
Description : A circuit which develops voltage across the horizontal deflection plates is known as a) Time base generator b) Electron gun c) Thermionic diode d) Zener diode
Last Answer : a) Time base generator
Description : ___________ is not affected by a magnetic field a) Change in magnetic flux b) a moving electron c) a stationary proton d) current flowing in a conductor
Last Answer : c) a stationary proton
Description : Two electron beams move parallel to each other. The nature of force between them is a) Attractive b) Repulsive c) Dependent on magnitude of velocity d) None
Last Answer : b) Repulsive
Description : An electron and a neutron enter a magnetic field with the same velocity. Ratio of electron to neutron’s acceleration is a) mn me b) √ mn me c) √ me mn d) me
Last Answer : a) mn me
Description : The minimum charge on any electron be less than: (a) 1.6×10−19C (b) 3.2×10−19C (c) 1.8×10−19C (d) 9.1×10−19C
Last Answer : (a) 1.6×10−19C
Description : Is the energy of an electron in 2s orbital same as of that in 2p orbital? Why?
Last Answer : Ans. No, the energy depends upon (n+l) values in an atom. Hence 2p orbital has greater energy than 2s.
Description : The azimuthal quantum number determines the: w) spin of an electron x) shape of an orbital y) size of an orbital z) energy of an orbital
Last Answer : ANSWER: X -- SHAPE OF AN ORBITAL
Description : The energy required to magnetize and demagnetize is called a) Saturation b) Retentivity c) Coercivity d) Hysteresis loss
Last Answer : d) Hysteresis loss
Description : The ratio of energy of the electron in ground state of hydrogen to the electron in first excited state of `Be^(3+)` is
Last Answer : The ratio of energy of the electron in ground state of hydrogen to the electron in first excited state of `Be^(3+)` is ... 8` C. `1 : 16` D. `16 : 1`
Description : An electron , in a hydrogen-like atom, is in excited state. It has a total energy of -3.4 eV. Calculate (a) the kinetic energy and (b) the de Broglie
Last Answer : An electron , in a hydrogen-like atom, is in excited state. It has a total energy of -3.4 ... and (b) the de Broglie wavelength of the electron.
Description : An electron in an excited hydrogen atom acquired an energy of 12.1 eV. To what energy level did it jump? How many spectral lines may be emitted in the
Last Answer : An electron in an excited hydrogen atom acquired an energy of 12.1 eV. To what ... to lower energy level? Calculate the corresponding wavelengths.
Description : The energy required to remove the electron from the outermost shell from a free and isolated atom of the element is called
Last Answer : Ionisation energy.