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: 0 to 1 eV

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: Is different for different materials

Question: The phenomenon of photoelectric effect was first explained by

• a) Einstein
• b) Planck
• c) Bohr
• d) Hallwach

Answer: Einstein

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

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: h e^–1

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: All of these

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

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: 4n and E

Question:

• a) 1.10 eV
• b) 1.36 eV
• c) 2.47 eV
• d) 0.43 eV

Answer: 1.10 eV

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: It becomes more than double

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: All of these

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: No electron is emitted

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: V₀

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

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: Zero

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: 310 nm

Question:

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

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: 2.2 pm

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

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: E/c

More Questions...................................

Question: The de Broglie wavelength of an electron in the n^th Bohr orbit is related to the radius R of the orbit as

• a)

  

• b) None of these
• c)

  

• d)

  

Answer:

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: 82.7

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: 12.27 Å

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: The wavelength of matter waves is independent of

• a) Charge
• b) Momentum
• c) Velocity
• d) Mass

Answer: Charge

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: The higher the momentum, the longer is the wave-length

Question: A proton and an alpha particle are accelerated through the same potential difference. The ratio of de Broglie wavelength of the proton to that of the alpha particle will be

• a)

  

• b) 1 : 2
• c) 1 : 1
• d) 2 : 1

Answer:

Question:

• a) 2 : 1
• b) 4 : 1
• c) 1 : 2
• d) 1 : 4

Answer: 2 : 1

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: Any particle in motion, whether charged or uncharged, is accompanied by matter waves

Question: Neglecting variation of mass with velocity, the wavelength associated with an electron having a kinetic energy E is proportional to

• a)

  

• b)

  

• c) E
• d) E^–2

Answer:

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:  An electron

Question:

• a) 5 p₀
• b) 4 p₀
• c)

  

• d)

  

Answer: 5 p₀

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: 1.03 V

Question:

• a) 24 × 10¹⁷
• b) 8 × 10¹⁹
• c) 48 × 10¹⁷
• d) 48 × 10¹⁹

Answer: 24 × 10¹⁷

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: Saturation current will decrease

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: 12400 Å

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: 0.2 nm

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

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: 1400 m/s

Question: Figure shows four situations in which an electron is moving in electric / magnetic field. In which case the de Broglie wavelength of electron is increasing?

• a)

  

• b)

  

• c)

  

• d)

  

Answer: