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

The light of wavelength 4000 A^o 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

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

Calculate the kinetic energy of the electron having wavelength 1 nm

• 2.1 eV

• 3.1 eV

• 1.5 eV

• 4.2 eV

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

• E^1/2

• E^3/2

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.

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

If the energy, E = G^p h^q c^r, 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

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.