NEET Physics Dual Nature of Radiation and Matter MCQs Set A

Question: The wavelength of a photon needed to remove a proton from a nucleus which is bound to the nuclear with 1 MeV energy is nearly
a) 1.2 × 10^–3 nm
b) 1.2 × 10 nm
c) 1.2 nm
d) 1.2 × 10^–6 nm
Answer: A

Question: Consider a beam of electrons (each electron with energy E₀) incident on a metal surface kept in an evacuated chamber. Then,
a) electrons can be emitted with any energy, with a maximum of E₀
b) None of these
c) electrons can be emitted but all with an energy, E₀
d) no electrons will be emitted as only photons can emit electrons
Answer: A

Question:  When the energy of the incident radiation is increased by 20%, the kinetic energy of the photoelectrons emitted from a metal surface increased from 0.5 eV to 0.8 eV. The work function of the metal is :
a) 1.0 eV
b) 1.3 eV
c) 1.5 eV
d) 0.65 eV
Answer: A

Question:  A 15.0 eV photon collides with and ionizes a hydrogen atom. If the atom was originally in the ground state (ionization potential =13.6 eV), what is the kinetic energy of the ejected electron?
a) 1.4 eV
b) 13.6 eV
c) 28.6 eV
d) 15.0 eV
Answer: A

Question:  Assertion : Photoelectric saturation current increases with mthe increase in frequency of incident light.
Reason : Energy of incident photons increases with increase in frequency and as a result photoelectric current increases.
a) Assertion is incorrect, reason is correct
b) Assertion is correct, reason is incorrect
c) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
d) Assertion is correct, reason is correct; reason is a correct explanation for assertion
Answer: A

Question: Assertion : In process of photoelectric emission, all emitted electrons do not have same kinetic energy.
Reason : If radiation falling on photosensitive surface of a metal consists of different wavelength then energy acquired by electrons absorbing photons of different wavelengths shall be different.
a) Assertion is correct, reason is correct; reason is a correct explanation for assertion.
b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
c) Assertion is correct, reason is incorrect
d) Assertion is incorrect, reason is correct.
Answer: A

Question:  When 0.50 Å X-rays strike a material, the photoelectrons from the k shell are observed to move in a circle of radius 23 mm in a magnetic field of 2 × 10^–2 tesla acting perpendicularly to the direction of emission of photoelectrons. What is the binding energy of k-shell electrons?
a) 6.2 keV
b) 2.9 keV
c) 5.5 keV
d) None of these
Answer: A