CBSE  /  Class 12  /  Physics  /  Nuclei

  • 1. 
    Radius of 1st Bohr orbit is a0 (= 0.529 Å) What is the radius of 2nd Bohr orbit?

  • 10-8
  • 2a0
  • 4a0
  • 2√2a0

  • 2. 
    The ground state energy of Hydrogen atom is -6 eV. What is the potential energy of electron in this state?

  • 0 eV
  • -13.6 eV
  • 2 eV
  • -27.2 eV

  • 3. 
    Which of the following atoms has the lowest ionization potential?

  • \(_{8}^{8}\)O
  • \(_{7}^{14}\)N
  • \(_{55}^{133}\)Cs
  • \(_{18}^{40}\)Ar

  • 4. 
    The Bohr model of atom:

  • assumes that the angular momentum of electron is quantized
  • uses Einstein's photoelectric equation
  • predicts continuous emission spectra for atoms
  • predicts the same emission spectra for all types of atoms

  • 5. 
    Nuclear force is:

  • strong, short range and charge independent force
  • charge independent, attractive and long range force
  • strong, charge dependent and short range attractive force
  • long range, change dependent and attractive force

  • 6. 
    If radio active nuclei emits β-particle, then mass-number:

  • increased by 1 unit
  • decreases by 1 unit
  • increases by 2 unit
  • decreases by 2 unit

  • 7. 
    An alpha particle is emitted from \(_{88}\)Ra\(^{226}\), then the product nuclei has:

  • Z = 84, A = 224
  • Z = 86, A = 224
  • Z = 86, A = 222
  • Z = 82, A = 222

  • 8. 
    X-ray was discovered by :

  • Becqueral
  • Marie curie
  • Roengton
  • Vanlaw

  • 9. 
    Fusion takes place at high temperature because:

  • Atom are ionised at high temperature
  • Molecules break up at high temperature
  • Nuclei break up at high temp.
  • Kinetic energy is high enough to overcome repulsion between nuclei

  • 10. 
    The order of nuclear density is :

  • 103
  • 1017
  • 106
  • None
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