Modern Physics Test Series

(A) Multple choice questions

1. Photoelectric emission takes place when
(a)electrons falls on photosensitive surface
(b)alpha particles falls on photosensitive surface
(c)light rays falls on photosensitive surface
(d)neutrons falls on photosensitive surface

2. The velocity of most energetic photo electrons emitted from metal surface depends on
(a) time for which radiation fall on metal surface
(b) the frequency of incident light
(c) the intensity of incident light
(d) none of the above

3. The work funcion of a metal is w and λ is the wavelength of incident radiation. there would be no emission of photoelectrons when
(a) λ > hc/w
(b) λ < hc/w
(c) λ = hc/w
(d) λ ≤ hc/w

4. The fact that was not inferred from the Rutherford model of the atom was that the
(a) nucleus occupied a small space inside the atom
(b) nucleus consisted of neutrons and protons
(c) electrons were outside the nucleus of the atom
(d) nucleus was dense in nature

5. A graph showing the energy of the photoelectron as a fuction of the frequency of the radiation for a given emitting surface is best represented as




(B) Matrix match type question
6. Match the items mentioned with those given in group (P) with those given in group (Q)

(a) The concept of nuclear atom was
established from the experiment on the
(b) Wave aspect of matter was confirmed by
(c) Bohr theory was successful in explaining
(d) Photons may cause

(1) emission of electrons from the metal surface
(2) scattering of alpha particles by a gold foil
(3) diffraction of electrons by a crystal
(4) bright line spectra of hydrogen atom
(5) scattering of X-rays by electrons

1. (c)
2. (b)
3. (a)
4. (c)
5. (a)
6. a-2

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