What is the approximate thickness of gold foil in
particle scattering experiment?
Q.1)
( 1 mark )
View Answer
(Q.2)
What is
particle?
( 1 mark )
View Answer
(Q.3) What is the order of radius of helium atom?
( 1 mark )
View Answer
(Q.4) Name the series of hydrogen spectrum which lies in the visible region of
electromagnetic spectrum?
( 1 mark )
View Answer
What is the energy possessed by an electron when n is
infinity ?
(Q.5)
( 1 mark )
View Answer
(Q.6) Name the series of hydrogen atom which lies in the U.V region.
( 1 mark )
View Answer
(Q.7) Can a hydrogen atom absorb a photon whose energy exceeds its binding
energy?
( 1 mark )
View Answer
(Q.8) Name the experiment which led to the discovery of atomic nucleus?
( 1 mark )
View Answer
(Q.9) Name the series of hydrogen spectrum lying in the infrared region.
( 1 mark )
View Answer
(Q.10) How is the impact parameter related to the scattering angle?
( 1 mark )
View Answer
(Q.11) Who proposed that the orbits of the electron in the atom are elliptical?
( 1 mark )
(A) Thomson
(B) Bohr
(C) Rutherford
(D) Sommerfield
View Answer
(Q.12) If an electron jumps from 1st orbit to 3rd orbit, then it will
( 1 mark )
(A) Absorb energy
(B) release energy
(C) No gain of energy
(D) none of these
View Answer
(Q.13) To explain his theory, Bohr used
( 1 mark )
(A) conservation of linear momentum
(B) conservation of angular momentum
(C) conservation of quantum frequency
(D) conservation of energy
View Answer
(Q.14) Which source is associated with a line emission spectrum?
(A) Electric fire
(B) Neon street sign
(C) Red traffic light
(D) Sun
View Answer
( 1 mark )
(Q.15) A gas of monoatomic hydrogen is bombarded with a stream of electrons
that have been accelerated from rest through a potential difference of 12.75 volt.
In the emission spectrum, one cannot observe any line of
( 1 mark )
(A) Lyman series
(B) Balmer series
(C) Paschen series
(D) Pfund series
View Answer
(Q.16) If the wavelength of the first line of the Balmer series of hydrogen is 6561
Å, the wavelength of the second line of the series should be
( 1 mark )
(A) 1312 Å
(B) 3280 Å
(C) 4860 Å
(D) 2187 Å
View Answer
(Q.17) The charge on the electron and protons is reduced to half. Let the present
value of the Rydberg constant be R. What will be the new value of the Rydberg
constant?
( 1 mark )
(A) R/2
(B) R/4
(C) R/8
(D) R/16
View Answer
The order of binding energy per nucleon for most
nuclides:
(Q.18)
( 1 mark )
(A) 7MeV/N
(B) 9MeV/N
(C) 8MeV/N
(D) 6MeV/N
View Answer
(Q.19) In a hydrogen atom, the electron in a given orbit has total energy –1.5 eV.
The potential energy is
( 1 mark )
(A) 1.5 eV
(B) –1.5 eV
(C) 3.0 eV
(D) 3.0 eV
View Answer
(Q.20) In a hypothetical Bohr hydrogen atom, the mass of the electron is
doubled. The energy E0 and radius r0 of the first orbit will be (a0 is the Bohr
radius).
( 1 mark )
(A)
(B)
(C)
(D)
View Answer
(Q.21) In terms of Bohr radius a0, the radius of the second Bohr orbit of a
hydrogen atom is given by
(A)
(B)
( 1 mark )
(C)
(D)
View Answer
The acceleration of electron in the first orbit of
hydrogen atom is
(Q.22)
( 1 mark )
(A)
(B)
(C)
(D)
View Answer
(Q.23) According to classical theory the proposed circular path of an electron in
Rutherford model of atom will be
( 1 mark )
(A) circular
(B) straight line
(C) parabolic
(D) spiral
View Answer
(Q.24) How does the energy difference between the consecutive energy level
vary as the quantum number 'n' increases?
( 1 mark )
(A) Increases
(B) Decreases
(C) Remains unchanged
(D) First increase and then decreases
View Answer
(Q.25) Which of the following is the property of Rydberg constant?
( 1 mark )
(A) It is universal constant
(B) It is same for all the hydrogen like atoms
(C) It depends on the atomic number of the atom
(D) It depends on the mass number of the atom
View Answer
(Q.26) Who explained the origin of the Fraunhoffer lines?
( 1 mark )
(A) Fraunhoffer
(B) Kirchoff
(C) Fresnel
(D) Snell
View Answer
(Q.27) When a hydrogen atom is raised from the ground state to an excited state
( 1 mark )
(A) P.E. increases and K.E. decreases
(B) P.E. decreases and K.E. increase
(C) both kinetic energy (K.E.) and potential energy (P.E.) increases
(D) both K.E. and P.E. decreases
View Answer
(Q.28) Rutherford's experiments on scattering of
(A) atom is mostly empty
(B) positive charge is uniformly distributed in the atom
( 1 mark )
(C) number of positive charges is equal to the number of negative charges
(D) atoms contain electrons
View Answer
(Q.29) Rutherford's atomic model accounts for :
( 1 mark )
(A) concentration of positive charge at the centre in the atom
(B) stability of electron orbits
(C) stability of the nucleus
(D) line spectrum of hydrogen
View Answer
(Q.30) Band spectrum is produced by
( 1 mark )
(A) H
(B) He
(C) H2
(D) Na
View Answer
(Q.31) The total energy of an electron in the excited state corresponding to n = 3
is E. What is its potential energy with proper sign?
( 1 mark )
(A) –2E
(B) 2E
(C) –E
(D) E
View Answer
(Q.32) The ionisation potential of hydrogen atom is 13.6 eV. How much energy
need to be supplied to ionise the hydrogen atom in the first excited state?
( 1 mark )
(A) 13.6 eV
(B) 27.2 eV
(C) 3.4 eV
(D) 6.8 eV
View Answer
(Q.33) The line spectrum is obtained when the incandescent vapours at low
pressure of the excited substance are in :
( 1 mark )
(A) atomic state
(B) molecular state
(C) plasma state
(D) ionised state
View Answer
(Q.34) When electron in hydrogen atom jumps to the inner most orbit, the
radiation emitted belongs to which one of the following series?
( 1 mark )
(A) Paschen
(B) Balmer
(C) Lyman
(D) Brackett
View Answer
(Q.35) What will be the angular momentum in fourth orbit if L is the angular
momentum of the electron in the second orbit of hydrogen atom?
(A)
(B)
(C) 2L
(D)
( 1 mark )
View Answer
(Q.36) The total energy of the electron orbiting around the nucleus in the ground
state of the atom is :
( 1 mark )
(A) less than zero
(B) zero
(C) more than zero
(D) sometimes less and sometime more than zero
View Answer
(Q.37) What is the value of fine structure Constant.
( 1 mark )
(A) 0.0027
(B) 0.072
(C) 0.73
(D) 0.0073
View Answer
(Q.38) What is the order of radius of helium atom?
( 1 mark )
(A) 10-5 m
(B) 10-7 m
(C) 10-10 m
(D) 10-8 m
View Answer
(Q.39) An alpha particle has
( 1 mark )
(A) a charge + e
(B) a charge -2e
(C) a mass equal to that of a deutron
(D) charge to mass ratio equal to that of a deuteron
View Answer
(Q.40) The energy of an electron in an excited hydrogen atom is -3.4 eV. What is
the angular momentum of the electron according to Bohr’s Theory? Planck’s
constant h= 6.67x10-34 Js.
( 1 mark )
(A) 1.22x10-23 Js
(B) 1.22x10-32 Js
(C) 1.22x10-34 Js
(D) 2.11x10-34 Js
View Answer
(Q.41) What will be the ratio of the radii of two nuclei of mass numbers A1 and
A2?
( 2 Marks )
View Answer
(Q.42) What are the drawbacks of Rutherford’s atom model?
( 2 Marks )
View Answer
(Q.43) Write the relation for:(i) The distance of closest approach.
(ii) Impact parameter.
( 2 Marks )
View Answer
(Q.44) What is the ground state energy of electron in case of 3Li7?
( 2 Marks )
View Answer
A stream of electrons traveling with a speed ‘v’ m/s at
right angles to a uniform electric field ‘E’ is deflected in a
(Q.45)
( 2 Marks )
circular path of radius ‘r’. Prove that,
View Answer
.
A 12.5 MeV
particle approaching a gold nucleus is
deflected back by 1800. How close does it approach the
nucleus?
(Q.46)
( 3 Marks )
View Answer
(Q.47) Determine the speed of the electron in the n = 3 orbit of He+. Is the nonrelativistic approximation valid?
( 3 Marks )
View Answer
(Q.48) Define electron volt and atomic mass unit. Calculate the energy in joules
equivalent to the mass of one proton.
( 3 Marks )
View Answer
In a hydrogen atom, an electron of charge ‘e’ revolves
in an orbit of radius ‘r’ with a speed ‘v’. Prove that the
magnetic moment associated with the electron is given by
(Q.49)
( 3 Marks )
.
View Answer
(Q.50) What are the main features of Rutherford’s atom model?
( 3 Marks )
View Answer
(Q.51) State the postulates of Bohr’s model of hydrogen atom. The electron, in a
given Bohr orbit has a total energy of -1.5 eV. Calculate its: (i) Kinetic Energy.(ii)
Potential energy.
View Answer
( 5 Marks )