How many electrons are contained in \(_{92}^{238}\)U nucleus?
  • 92
  • 146
  • 238
  • 0
Chadwick was awarded the Nobel prize in Physics in 1935 for his discovery of:
  • electron
  • proton
  • neutron
  • None of these
The density of a nucleus is of the order of:
  • 1015 kg m-3
  • 1018 kg m-3
  • 1017 kg m-3
  • 1016 kg m-3
When the mass of a sample of a radioactive substance decreases, the mean life of the sample:
  • increases
  • decreases
  • remain unchanged
  • first decreases then increases
Alpha particle emitted from a radioactive material are:
  • Helium nuclei
  • Hydrogen nuclei
  • Lithium nuclei
  • None of the above
The half life of a radioactive decay is n times its mean life, n is equal to:
  • 0.6930
  • 0.0693
  • \(\frac{1}{0.6930}\)
  • 0.3070
Rutherford is the unit of:
  • radioactivity
  • energy
  • photoelectric current
  • magnetic field
According to Yukawa's theory of nuclear forces, the origin of nuclear force between nucleons is due to the exchange of
  • mesons
  • photons
  • electrons
  • positrons
An electron and a positron each having a mass equivalent to 0.53 MeV annihilate each other and produce a photon. The minimum energy of the photon is.
  • 0.53 MeV
  • 1.06 MeV
  • 2.12 MeV
  • zero
The wavelength of y-rays is of the order of:
  • 10-8 m
  • 10-5 m
  • 10-11 m
  • 10-22 m
Radius of 1st Bohr orbit is a0 (= 0.529 Å) What is the radius of 2nd Bohr orbit?
  • 10-8
  • 2a0
  • 4a0
  • 2√2a0
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
Which of the following atoms has the lowest ionization potential?
  • \(_{8}^{8}\)O
  • \(_{7}^{14}\)N
  • \(_{55}^{133}\)Cs
  • \(_{18}^{40}\)Ar
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
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
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
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
X-ray was discovered by :
  • Becqueral
  • Marie curie
  • Roengton
  • Vanlaw
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
The order of nuclear density is :
  • 103
  • 1017
  • 106
  • None
0 h : 0 m : 1 s

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