Question : According to classical theory, the path of an electron in Rutherford atomic model is
(a) spiral
(b) circular
(c) parabolic
(d) straight line
Answer: A
Question : Rutherford’s a-particle experiment showed that the atoms have
(a) Proton
(b) Nucleus
(c) Neutron
(d) Electrons
Answer: B
Question : Rutherford’s atomic model was unstable because
(a) nuclei will break down
(b) electrons do not remain in orbit
(c) orbiting electrons radiate energy
(d) electrons are repelled by the nucleus
Answer: B
Question : According to Bohr’s model of hydrogen atom
(a) the linear velocity of the electron is quantised
(b) the angular velocity of the electron is quantised
(c) the linear momentum of the electron is quantised
(d) the angular momentum of the electron is quantised
Answer: D
Question : As the quantum number increases, the difference of energy between consecutive energy levels
(a) remain the same
(b) increases
(c) decreases
(d) sometimes increases and sometimes decreases.
Answer: C
Question : When hydrogen atom is in its first excited level, it’s radius is
(a) four times, it ground state radius
(b) twice times, it ground state radius
(c) same times, it ground state radius
(d) half times, it ground state radius.
Answer: A
Question : Which of the following series in the spectrum of hydrogen atom lies in the visible region of the electromagnetic spectrum?
(a) Paschen series
(b) Balmer series
(c) Lyman series
(d) Brackett series
Answer: B
Question : The Balmer series for the H-atom can be observed
(a) if we measure the frequencies of light emitted when an excited atom falls to the ground state
(b) if we measure the frequencies of light emitted due to transitions between excited states and the first excited state
(c) in any transition in a H-atom
(d) None of these
Answer: B
Question : In a hydrogen atom, which of the following electronic transitions would involve the maximum energy change
(a) n = 2 to n = 1
(b) n = 3 to n = 1
(c) n = 4 to n = 2
(d) n = 3 to n = 2
Answer: B
Question : The Lyman transitions involve
(a) largest changes of energy
(b) smallest changes of energy
(c) largest changes of potential energy
(d) smallest changes of potential energy
Answer: A
Question : The first model of atom was proposed by
(a) Hans Geiger
(b) Ernst Rutherford
(c) J.J. Thomson
(b) N.H.D Bohr
Question : The empirical atom model was given by
(a) J. J. Thomson
(b) Rutherford
(c) Niels Bohr
(d) Sommerfeld
Answer: A
Question : Which of the following statements is correct in case of Thomson’s atomic model?
(a) It explains the phenomenon of thermionic emission, photoelectric emission and ionisation.
(b) It could not explain emission of line spectra by elements.
(c) It could not explain scattering of α-particles
(d) All of the above
Answer: C
Question : Which one did Rutherford consider to be supported by the results of experiments in which α-particles were scattered by gold foil?
(a) The nucleus of an atom is held together by forces which are much stronger than electrical or gravitational forces.
(b) The force of repulsion between an atomic nucleus and an α-particle varies with distance according to inverse square law.
(c) α-particles are nuclei of Helium atoms.
(d) Atoms can exist with a series of discrete energy levels
Answer: B
Question : According to the Rutherford’s atomic model, the electrons inside the atom are
(a) stationary
(b) not stationary
(c) centralized
(d) None of these
Answer: B
Question : According to classical theory, the circular path of an electron in Rutherford atom model is
(a) spiral
(b) circular
(c) parabolic
(d) straight line
Answer: A
Question : Rutherford’s α-particle experiment showed that the atoms have
(a) Proton
(b) Nucleus
(c) Neutron
(d) Electrons
Answer: B
Question : Electrons in the atom are held to the nucleus by
(a) coulomb’s force
(b) nuclear force
(c) vander waal’s force
(d) gravitational force
Answer: A
Question : The Rutherford α-particle experiment shows that most of the α-particles pass through almost unscattered while some are scattered through large angles. What information does it give about the structure of the atom?
(a) Atom is hollow.
(b) The whole mass of the atom is concentrated in a small centre called nucleus
(c) Nucleus is positively charged
(d) All of the above
Question : In Rutherford's α -particle scattering experiment, what will be correct angle for α scattering for an impact parameter b : 0 ?
(a) 90º
(b) 270º
(c) 0º
(d) 180º
Question : In the ground state in ...A... electrons are in stable equilibrium while in ...B... electrons always experiences a net force. Here, A and B refer to
(a) Dalton’s theory, Rutherford model
(b) Rutherford’s model, Bohr’s model
(c) Thomson’s model, Rutherford’s model
(d) Rutherford’s model, Thomson’s model
Answer: C
Question : The significant result deduced from the Rutherford's scattering experiment is that
(a) whole of the positive charge is concentrated at the centre of atom
(b) there are neutrons inside the nucleus
(c) α-particles are helium nuclei
(d) electrons are embedded in the atom
(e) electrons are revolving around the nucleus
Answer: A
Question : Electrons in the atom are held to the nucleus by
(a) coulomb’s force
(b) nuclear force
(c) vander waal’s force
(d) gravitational force
Answer: C
Question : In a Rutherford scattering experiment when a projectile of charge Z1 and mass M1approaches a target nucleus of charge Z2 and mass M2, the distance of closest approach is r0. The energy of the projectile is
(a) directly proportional to Z1 Z2
(b) inversely proportional to Z1
(c) directly proportional to mass M1
(d) directly proportional to M1 × M2
Answer: A
Question : According to classical theory, Rutherford’s atomic model is
(a) stable
(b) unstable
(c) meta stable
(d) both (a) and (b)
Question : Rutherford’s atomic model was unstable because
(a) nuclei will break down
(b) electrons do not remain in orbit
(c) orbiting electrons radiate energy
(d) electrons are repelled by the nucleus
Answer: B
Question : The electrons of Rutherford’s model would be expected to lose energy because, they
(a) move randomly
(b) jump on nucleus
(c) radiate electromagnetic waves
(d) escape from the atom
Answer: C
Question : As one considers orbits with higher values of n in a hydrogen atom, the electric potential energy of the atom
(a) decreases
(b) increases
(c) remains the same
(d) does not increase
Answer: B
Question : Which of the following parameters is the same for all hydrogen-like atoms and ions in their ground states?
(a) Radius of the orbit
(b) Speed of the electron
(c) Energy of the atom
(d) Orbital angular momentum of the electron
Question : The angular speed of the electron in the nth orbit of Bohr hydrogen atom is
(a) directly proportional to n
(b) inversely proportional to n
(c) inversely proportional to n2
(d) inversely proportional to n3
Question : According to Bohr’s model of hydrogen atom
(a) the linear velocity of the electron is quantised.
(b) the angular velocity of the electron is quantised.
(c) the linear momentum of the electron is quantised.
(d) the angular momentum of the electron is quantised.
Question : As the quantum number increases, the difference of energy between consecutive energy levels
(a) remain the same
(b) increases
(c) decreases
(d) sometimes increases and sometimes decreases.
Answer: C
Question : Which of the following in a hydrogen atom is independent of the principal quantum number n? (The symbols have their usual meanings).
(a) νn
(b) Er
(c) En
(d) νr
Answer: B
Question : In terms of Bohr radius r0, the radius of the second Bohr orbit of a hydrogen atom is given by
(a) 4 r0
(b) 8 r0
(c) 2 r0
(d) 2 r0
Answer: A
Question : When hydrogen atom is in its first excited level, it’s radius is
(a) four times, it ground state radius
(b) twice times, it ground state radius
(c) same times, it ground state radius
(d) half times, it ground state radius
Answer: A
Question : The angular momentum of the electron in hydrogen atom in the ground state is
(a) 2h
(b) h/2
(c) h/2π
(d) h/4π
Answer: C
Question : When an atomic gas or vapour is excited at low pressure, by passing an electric current through it then
(a) emission spectrum is observed
(b) absorption spectrucm is observed
(c) band spectrum is observed
(d) both (b) and (c)
Answer: A
Question : The first spectral series was disscovered by
(a) Balmer
(b) Lyman
(c) Paschen
(d) Pfund
Answer: B
Question : When an electron jumps from the fourth orbit to the second orbit, one gets the
(a) second line of Paschen series
(b) second line of Balmer series
(c) first line of Pfund series
(d) second line of Lyman series
Answer: A
Question : The Balmer series for the H-atom can be observed
(a) if we measure the frequencies of light emitted when an excited atom falls to the ground state
(b) if we measure the frequencies of light emitted due to transitions between excited states and the first excited state
(c) in any transition in a H-atom
(d) None of these
Answer: B
Question : In Balmer series of emission spectrum of hydrogen, first four lines with different wavelength Hα Hβ Hγ and Hδ are obtained. Which line has maximum frequency out of these?
(a) Hα
(b) Hβ
(c) Hγ
(d) Hδ
Question : In which of the following series, does the 121.5 nm line of the spectrum of the hydrogen atom lie ?
(a) Lyman series
(b) Balmer series
(c) Paschen series
(d) Brackett series.
Answer: A
Question : Which of the following series in the spectrum of hydrogen atom lies in the visible region of the electromagnetic spectrum?
(a) Paschen series
(b) Balmer series
(c) Lyman series
(d) Brackett series
Answer: B
Question : The shortest wavelength in Balmer’s series for Hydrogen atom is ...A... and this is obtained by substituting ...B ... in Balmer’s formula. Here, A and B refer to
(a) 656.3 nm, n : 3
(b) 486.1 nm, n : 4
(c) 410.2 nm, n : 5
(d) 364.6 nm, n :
Question : As an electron makes a transition from an excited state to the ground state of a hydrogen - like atom/ion
(a) kinetic energy decreases, potential energy increases but total energy remains same
(b) kinetic energy and total energy decrease but potential energy increases
(c) its kinetic energy increases but potential energy and total energy decrease
(d) kinetic energy, potential energy and total energy decrease
Answer: C
Question : Which of the following series in the spectrum of hydrogen atom lies in the visible region of the electromagnetic spectrum?
(a) Paschen series
(b) Balmer series
(c) Lyman series
(d) Brackett series
Answer: B
Question : In a hydrogen atom, which of the following electronic transitions would involve the maximum energy change
(a) n = 2 to n = 1
(b) n = 3 to n = 1
(c) n = 4 to n = 2
(d) n = 3 to n = 2
Answer: B
Question : Hydrogen atom excites energy level from fundamental state to n : 3. Number of spectral lines according to Bohr, is
(a) 4
(b) 3
(c) 1
(d) 2
Answer: B
Question : The transition from the state n : 4 to n : 3 in a hydrogen like atom results in ultraviolet radiation. Infrared radiation will be obtained in the transition from
(a) 2 → 1
(b) 3 → 2
(c) 4 → 2
(d) 5 → 4
Question : For a given value of n, the number of electrons in an orbit is
(a) n
(b) n2
(c) 2n2
(d) 2n
Answer: C
Question : Bohr’s atom model is the modification of Rutherford’s atom model by the application of
(a) newton's theory
(b) huygen’s theory
(c) maxwell’s theory
(d) planck’s quantum theory
Question : In Bohr’s model electrons are revolving in a circular orbits around the nucleus called as
(a) stationary orbits
(b) non radiating orbits
(c) Bohr’s orbits
(d) all of these
Question : According to Bohr’s theory of H atom, an electron can revolve around a proton indefinitely, if its path is
(a) a perfect circle of any radius
(b) a circle of an allowed radius
(c) a circle of constantly decreasing radius
(d) an ellipse with fixed focus
Answer: B
Question : According to Bohr the difference between the energies of the electron in the two orbits is equal to
(a) hν
(b) hc/λ
(c) both (a) and (b)
(d) neither (a) nor (b)
Answer: C
Question : The angular momentum of electrons in an atom produces
(a) magnetic moment
(b) ZEEMAN effect
(c) light
(d) nuclear fission
Answer: A
Question : According to Planck’s quantum theory any electromagnetic radiation is
(a) continuously emitted
(b) continuously absorbed
(c) emitted or absorbed in discrete units
(d) None of these
Answer: C
Question : In Bohr model of hydrogen atom, let P.E. represents potential energy and T.E. represents the total energy. In going to a higher level.
(a) P. E. decreases, T.E. increases
(b) P. E. increases, T.E. decreases
(c) P. E. decreases, T.E. decreases
(d) P. E. increases, T.E. increases
Question : Which of the following are in the ascending order of wavelength?
(a) Hα, Hβ and Hγ lines of Balmer series
(b) Lyman limit, Balmer limit
(c) Violet, blue, yellow, red colours in solar spectrum
(d) both (b) and (c)
Question : Rydberg’s constant is
(a) same for all elements
(b) different for different elements
(c) a universal constants
(d) is different for lighter elements but same for heavier elements
Answer: B
Question : In the hydrogen atom, an electron makes a transition from n : 2 to n : 1. The magnetic field produced by the circulating electron at the nucleus
(a) decreases 16 times
(b) increases 4 times
(c) decreases 4 times
(d) increases 32 times
Answer: D
Question : The ionization energy of hydrogen atom is 13.6 eV. Following Bohr’s theory, the energy corresponding to a transition between 3rd and 4th orbit is
(a) 3.40 eV
(b) 1.51 eV
(c) 0.85 eV
(d) 0.66 eV
Answer: D
Question : The largest wavelength in the ultraviolet region of the hydrogen spectrum is 122 nm. The smallest wavelength in the infrared region of the hydrogen spectrum (to the nearest integer) is
(a) 802 nm
(b) 823 nm
(c) 1882 nm
(d) 1648 nm
Answer: B
Question : Out of the following which one is not a possible energy for a photon to be emitted by hydrogen atom according to Bohr’s atomic model?
(a) 1.9 eV
(b) 11.1 eV
(c) 13.6 eV
(d) 0.65 eV
Answer: B
Question : If 13.6 eV energy is required to ionize the hydrogen atom, then the energy required to remove an electron from n : 2 is
(a) 10.2 eV
(b) 0 eV
(c) 3.4 eV
(d) 6.8 eV.
Answer: C
Question : Energy required for the electron excitation in Li++ from the first to the third Bohr orbit is
(a) 36.3 eV
(b) 108.8 eV
(c) 122.4 eV
(d) 12.1 eV
Answer: B
Question : The ratio of the energies of the hydrogen atom in its first to second excited states is
(a) 1/4
(b) 4/9
(c) 9/4
(d) 4
Answer: C
Question : Excitation energy of a hydrogen like ion in its excitation state is 40.8 eV. Energy needed to remove the electron from the ion in ground state is
(a) 54.4 eV
(b) 13.6 eV
(c) 40.8 eV
(d) 27.2 eV
Answer: A
Question : Suppose potential energy between electron and proton at separation r is given by U : K ln (r), where K is a constant. For such a hypothetical hydrogen atom, the ratio of energy difference between energy levels (n : 1 and n : 2) and (n : 2 and n : 4) is
(a) 1
(b) 2
(c) 3
(d) 4
Answer: A
Question : An unknown hot gas emits radiation of wavelengths 46.0 nm, 82.8 nm and 103.5 nm only. Assume that the atoms have only two excited states and the difference between consecutive energy levels decreases as energy is increased. Taking the energy of the highest energy state to be zero, find the energies of the ground state and the first excited state.
(a) –27 eV, – 12 eV
(b) –6 eV, – 3 eV
(c) –11 eV, – 8 eV
(d) –9 eV, – 3 eV
Answer: A
