Physics - Atoms , Molecules And Nuclei

Question - 1

In Rutherford's experiment, silver foil is replaced by a copper foil of the same thickness. The number of alpha particles scattered through the same angle per minute in copper foil is proportional to

  • A \(\frac { { Z }_{ Cu } }{ { Z }_{ Ag } } \)
  • B \({ \left( \frac { { Z }_{ Cu } }{ { Z }_{ Ag } } \right) }^{ 2 }\)
  • C \(\frac { { Z }_{ Ag } }{ { Z }_{ Cu } } \)
  • D \({ \left( \frac { { Z }_{ Ag } }{ { Z }_{ Cu } } \right) }^{ 2 }\)

Question - 2

Alpha particles that come closer to nuclei

  • A are deflected more
  • B are deflected less
  • C are slowed down more
  • D make more collisions with nuclei

Question - 3

In Rutherford's experiment on alpha particle scattering, the ratio of number of alpha particles through an angle of 60° and 90° is

  • A 4 : 1
  • B \(\sqrt { 3 } :1\)
  • C 3 : 1
  • D 9 : 1

Question - 4

Rutherford's atomic model has the deficiencies, namely, 

  • A since electron has centripetal acceleration, it must fall into nucleus along a spiral path
  • B there must be infinite number of orbits
  • C both (a) and (b)
  • D None of (a) and (b)

Question - 5

Choose CORRECT statement

  • A Rutherford's scattering experiment proves the existence of positively charged nucleus
  • B The trijectory of a scattered alpha-particle is a hyperpola
  • C According to Maxwell's classical theory of electro-magnetic theory, the Rutherford model of atom is unstable
  • D ALL OF THE ABOVE

Question - 6

Choose INCORRECT statement :

  • A The nuclear atomic model was first proposed by J.J Thomson
  • B The nuclear atomic model was first proposed by E.Rutherford
  • C The shape of electron orbits proposed by Rutherford is circular
  • D According to classical theory the proposed circular path of an electron in Rutherford atom will be spiral

Question - 7

Rutherford's alpha-particle scattering experiment gave experimental information about

  • A the charge on alpha-particle
  • B the size of atom
  • C the size of nucleus
  • D the force between alpha-particle and proton in the nucleus

Question - 8

The size of atom is nearly equal to

  • A 1 nm
  • B 1 micron
  • C \(1\dot { A } \)
  • D 1 fermi

Question - 9

An electron revolves round the nucleus of charge Ze. In order to excite the electron from the state n =2 to n =3, the energy required is 47.2 eV. The value of Z is

  • A 3
  • B 2
  • C 5
  • D 4

Question - 10

The ionisation energy of hydrogen is 13.6 eV. Following Bohr's theory, the energy corresponding to a transition between the 3rd and the 4th orbit is

  • A 3.4 eV
  • B 1.51 eV
  • C 0.85 eV
  • D 0.66 eV
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