If an electron and a photon propagate in the form of waves h

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 Multiple Choice QuestionsMultiple Choice Questions

161.

Assertion: The photoelectrons produced by a monochromatic light beam incident on a metal
surface, have a spread in their kinetic energies. 

Reason: The work function of the metal varies as a function of depth from the surface.

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

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

  • If assertion is true, but reason is false

  • Both assertion and reason are false statements


162.

Assertion: The energy (E) and momentum (p) of a phoon are related by p = E/c.

Reason: the photon behaves like a particle.

  • 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


163.

A leaf which contains only green pigments is illuminated by a  laser light of wavelength  0.6328 μm. It would appear to be

  • brown

  • black

  • red

  • green


164.

A photon of energy 4 eV is incident on a metal surface whose work function is 2 eV. The minimum reverse potential to be applied for stopping the emission of electrons is

  • 2 V

  • 4 V

  • 6 V

  • 8 V


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165.

We wish to see inside an atom. Assuming the atom to have a diameter of  100 pm, this means that one must be able to resolve a width of say 10 pm. If an electron microscope is used, the minimum electron energy required is about

  • 1.5 keV

  • 15 keV

  • 150 keV

  • 1.5 keV


166.

Assertion:  A red object appears dark in the yellow light.

Reason: The red colour is scattered less.

  • 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


167.

Assertion:  Photoelectric effect demonstrates the wave nature of light.

Reason: The number of photoelectrons is proportional to the frequency of light

  • 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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168.

If an electron and a photon propagate in the form of waves having the same wavelength, it implies that they have the same

  • energy

  • momentum

  • velocity

  • angular momentum


B.

momentum

The de-Broglie wavelength of a particle or a photon is given by

   λ  =  hp

where h is the Planck's constant

          p is the momentum

As the electron and the photon are having the same wavelength λ, the momentum of both them will be the same.


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169.

Characteristic X-rays are produced due to

  • transfer of momentum in collision of electrons with target atoms

  • transition of electron from higher to lower electrons orbits in an atom

  • heating of the target

  • transfer of energy in collision of electrons with atoms in the target


170.

Assertion:  A tube light emits white light. 

Reason: Emission of light in a tube takes place at a very high temperature.

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

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

  • if assertion is true but reason is false

  • if both assertion and reason are false statements


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