JEE Physics Dual Nature Of Radiation and Matter MCQs Set A

Question. When photon of energy 3.8 eV falls on metallic surface of work function 2.8 eV, then the kinetic energy of emitted electrons are
(a) 0 to 1 eV
(b) 2.8 eV
(c) 6.6 eV
(d) 1 eV

Answer: A

Question. The photoelectric work function
(a) Is different for different materials
(b) Depends upon frequency of the incident light
(c) Is same for all metals
(d) Depends upon intensity of the incident light

Answer: A

Question. The phenomenon of photoelectric effect was first explained by
(a) Einstein
(b) Planck
(c) Bohr
(d) Hallwach

Answer: A

Question. In photoelectric effect, the slope of stopping potential versus frequency of incident light for a given surface will be
(a) h e^–1
(b) e h
(c) e
(d) h

Answer: A

Question. The energy of the most energetic photoelectrons emitted from a metal target depends upon
(a) All of these
(b) Photoelectric work function of the metal
(c) Threshold frequency of the metal
(d) Wavelength of the incident radiation

Answer: A

Question. A monochromatic point source of light is placed at a distance d from a metal surface. Photo electrons are ejected at a rate n per second, and with maximum kinetic energy E. If the source is brought nearer to distance d/2, the rate and the maximum kinetic energy per photoelectron become nearly
(a) 4n and E
(b) n and 4E
(c) 4n and 4E
(d) 2n and 2E

Answer: A

Question. If the frequency of light incident on a metallic plate be doubled, how will the maximum kinetic energy of the photoelectrons change?
(a) It becomes more than double
(b) It becomes exactly double
(c) It becomes less than double
(d) It does not change

Answer: A

Question. Wave nature of light cannot explain photoelectric effect because in photoelectric effect, it is seen that
(a) All of these
(b) There is no time lag between the incidence of radiation and emission of electrons
(c) Maximum kinetic energy of ejected electrons is independent of intensity of radiation
(d) For the frequency of light below a certain value, the photoelectric effect does not take place, irrespective of intensity

Answer: A

Question. The photoelectric threshold for a certain metal surface is 330 Å. What is the maximum kinetic energy of the photoelectrons emitted, if radiations of wavelength 1100 Å are used ?
(a) No electron is emitted
(b) 7.5 eV
(c) 2 eV
(d) 1 eV

Answer: A

Question. When a point source of light is at a distance of 50 cm from a photoelectric cell, the cut-off voltage is found to be V₀. If the same source is placed at a distance of 1 m from the cell, then the cut-off voltage will be
(a) V₀
(b) 2 V₀
(c) V₀/2
(d) V₀/4

Answer: A

Question. Light of frequency 1.5 times the threshold frequency is incident on photo-sensitive material. If the frequency is halved and intensity is doubled, the photo current becomes
(a) Zero
(b) Halved
(c) Doubled
(d) Quadrupled

Answer: A

Question. The work function of a substance is 4eV. The longest wavelength of light that can cause the emission of photoelectrons from this substance is approximately
(a) 310 nm
(b) 220 nm
(c) 400 nm
(d) 540 nm

Answer: A

Question. X-rays of wavelength 22 pm are scattered from a carbon target at an angle of 85° to the incident beam. The Compton shift for X-rays is
(a) 2.2 pm
(b) 1.1 pm
(c) 0.55 pm
(d) 4.4 pm

Answer: A

Question. If the energy of a photon is E, then its momentum is (c is velocity of light)
(a) E/c
(b) E/2c
(c) 2E/c
(d) It has no momentum

Answer: A

Question. A photon and an electron both have wavelength 1Å. The ratio of energy of photon to that of electron is
(a) 82.7
(b) 10^–10
(c) 0.012
(d) 1

Answer: A

Question. Wavelength of an electron accelerated through a potential difference of 1 volt is
(a) 12.27 Å
(b) 1.234 Å
(c) 1 micron
(d) 1 fermi

Answer: A

Question. The wavelength of matter waves is independent of
(a) Charge
(b) Momentum
(c) Velocity
(d) Mass

Answer: A

Question. Which one of the following statements is not true about de-Broglie waves ?
(a) The higher the momentum, the longer is the wave-length
(b) All atomic particles in motion have waves of a definite wavelength associated with them
(c) The faster the particle, the shorter is the wave-length
(d) For the same velocity, a heavier particle has a shorter wavelength

Answer: A

Question. Choose the only correct statement out of the following
(a) Any particle in motion, whether charged or uncharged, is accompanied by matter waves
(b) No particle, whether at rest or in motion, is ever accompanied by matter waves
(c) Only subatomic particles in motion are accompanied by matter waves
(d) Only a charged particle in motion is accompanied by matter waves

Answer: A

Question. Of the following having the same kinetic energy, the one which has the largest wavelength is
(a) An electron
(b) A proton
(c) A neutron
(d) An alpha particle

Answer: A

Question. If in a photoelectric cell, the wavelength of incident light is changed from 4000 Å to 3000 Å then change in stopping potential will be
(a) 1.03 V
(b) 0.66 V
(c) 0.33 V
(d) 0.49 V

Answer: A

Question. In photoelectric effect, if a weak intensity radiation instead of strong intensity of suitable frequency is used then
(a) Saturation current will decrease
(b) Photoelectric effect will not take place
(c) Photoelectric effect will get delayed
(d) Maximum kinetic energy will decrease

Answer: A

Question. The work function of tungsten is 4.50 eV. The wavelength of fastest electron emitted when light whose photon energy is 5.50 eV falls on tungsten surface, is
(a) 12400 Å
(b) 1.227 Å
(c) 0.286 Å
(d) 12.27 Å

Answer: A

Question. A proton is accelerated through 225 V. Its de Broglie wavelength is
(a) 0.2 nm
(b) 0.3 nm
(c) 0.4 nm
(d) 0.1 nm

Answer: A

Question. What should be the velocity of an electron so that its momentum becomes equal to that of a photon of wavelength 5200 Å?
(a) 1400 m/s
(b) 2800 m/s
(c) 1000 m/s
(d) 700 m/s

Answer: A