Assertion:  There is a physical significance of matter

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 Multiple Choice QuestionsMultiple Choice Questions

141.

Photoelectric effect supports quantum nature of light because

  • there is minimum frequency of light below which no photoelectrons are emitted

  • the maximum energy of photoelectron depends only on the frequency of light and not on its intensity

  • photoelectric effect is an instantaneous process

  • all the above choices are correct


142.

The light of wavelength 4000 Ao falls on a photosensitive substance whose work function is 2 eV. Its stopping potential is

  • 1.1 V

  • 1.8 V

  • 1.26 V

  • 0.8 V


143.

Assertion:  An electron microscope is based on de Broglie hypothesis. 

Reason:  A beam of electrons behaves as a wave which can be converged by electric and magnetic lenses.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


144.

If velocity of a particle is three times of that of electron and ratio of de Broglie wavelength of particle to that of electron is 1.814 x 10-4. The particle will be

  • Neutron

  • Deuteron

  • Alpha

  • Tritium


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145.

Calculate the kinetic energy of the electron having wavelength 1 nm

  • 2.1 eV

  • 3.1 eV

  • 1.5 eV

  • 4.2 eV


146.

If we assume kinetic energy of a proton is equal to energy of the photon, the ratio of de Broglie wavelength of proton to photon is proportional to

  • E

  • E-1/2

  • E1/2

  • E3/2


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147.

Assertion:  There is a physical significance of matter waves. 

Reason:  Both interference and diffraction occurs in it.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


A.

If both assertion and reason are true and reason is the correct explanation of assertion.

Matter waves are central part of the theory of quantum mechanics, being an example of wave-particle duality. All matter can exhibit wave-like behavior.

For example, a beam of electrons can be diffracted just like a beam of light or a water wave. It is an example of diffraction. 


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148.

If  K1 and K2 are maximum kinetic energies of photoelectrons emitted when lights of wavelengths  λ1 and λ2 respectively incident on a metallic surface. If  λ1 = 3λ2, then

  • K1 > ( K2 / 3)

  • K1 < ( K2/3)

  • K1 = 2 K2

  • K2 = 2K1


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149.

If the energy, E = Gp hq cr, where G is the universal gravitational constant, h is the Planck's constant, h is the Planck's constant and c is the velocity of light, then the values of p, q and r respectively

  • -1/2, 1/2 and 5/2

  • 1/2, -1/2 and -5/2

  • -1/2, 1/2 and 3/2

  • 1/2, -/2 and -3/2


150.

Assertion:  The de Broglie equation has significance for any microscopic or submicroscopic particles. 

Reason:  The de Broglie wavelength inversely proportional to the mass of the object if velocity is constant.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


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