The energy of hydrogen atom in its ground state is -13.6 eV. The

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 Multiple Choice QuestionsMultiple Choice Questions

51.

A certain metal when irradiated by light (r = 3.2 × 1016 Hz) emits photoelectrons with twice kinetic energy as did photoelectrons when the same metal is irradiated by light (r = 2.0 × 1016 Hz). The v0 of metal is

  • 1.2 × 1014 Hz

  • 8 × 1015 Hz

  • 1.2 × 1016 Hz

  • 4 × 1012 Hz


52.

The radio-isotope used for treatment of thyroid disorders is

  • Na-24

  • P-32

  • Co-60

  • I-131


53.

A radioactive element X emits 3α, 1β and 1γ-particles and forms 76Y235. Element X is

  • 81X247

  • 80X247

  • 81X246

  • 80X246


54.

The radius of Na+ is 95 pm and that of Cl- ion is 181 pm. Hence, the coordination number of Na+ will be

  • 4

  • 6

  • 8

  • unpredictable


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55.

The wavelengths of electron waves in two orbits is 3: 5. The ratio of kinetic energy of electrons will be

  • 25: 9

  • 5: 3

  • 9: 25

  • 3: 5


56.

Electrons with a kinetic energy of 6.023 x 10J/mol are evolved from the surface of a metal, when it is exposed to radiation of wavelength of 600 nm. The minimum amount of energy required to remove an electron from the metal atom is

  • 2.3125 x 10-19 J

  • 3 x 10-19 J

  • 6.02 x 10-19 J

  • 6.62 x 10-19 J


57.

A nuclear reaction of U92235 with a neutron produces Kr3690 and two neutrons. Other element produced in this reaction is

  • Te52137

  • Cs55144

  • Ba56137

  • Ba56144


58.

On an X-ray diffraction photograph the intensity of the spots depends on:

  • neutron density of the atoms/ions

  • electron density of the atoms/ions

  • proton density of the atoms/ions

  • photon density of the atoms/ions


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59.

The energy of hydrogen atom in its ground state is -13.6 eV. The energy of the level corresponding to the quantum number n = 5 is

  • -5.4 eV

  • -0.54 eV

  • -2.72 eV

  • -0.85 eV


B.

-0.54 eV

Energy of e- in nth orbit of atom =-13.6n2 eV/ atomGiven, n= 5E5 = -13.6(5)2 =-13.625 = -0.54 eV/atm


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60.

Th23290  Pb20882. The number of α and β-particles emitted during the above reaction is

  • 8α and 4β

  • 8α and 16β

  • 4α and 2β

  • 6α and 4β


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