JEE Questions for Physics Dual Nature Of Radiation And Matter Quiz 3 - MCQExams.com

The kinetic energy of an electron, which is accelerated in the potential difference of 100 V, is
  • 1.6 × 10-17 J
  • 1.6 × 10-14 J
  • 1.6 × 10-10 J
  • 1.6 × 10-8 J
An electron initially at rest is accelerated through a potential difference of 1V. The energy acquired by electron is
  • 10 -19 J
  • 1.6 × 10 -19 erg
  • 1.6 × 10 -19 J
  • 1J
The energy that should be added to an electron to reduce its de-Broglie wavelength from 1 nm to 0.5 nm is
  • four times the initial energy
  • equal to the initial energy
  • twice the initial energy
  • thrice the initial energy
An electron and a neutron can have same (i) kinetic energy, (ii) momentum, or (iii) speed. Which particle has the shorter de–Broglie wavelength?
  • Neutron, same, neutron
  • Neutron, electron, same
  • Electron,same, neutron
  • Electron, neutron, electron

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  • 2)
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  • 1 : 1
For an electron, in the second orbit of Bohr's hydrogen atom, the moment of linear momentum is
  • πh
  • 2πh

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Sharp peak point A represents
Physics-Dual Nature of Radiation and Matter-67353.png
  • characteristic X–rays
  • continuous X–rays
  • Bremsstrahlung
  • discontinuous spectrum
X–rays of wavelength 0.140 nm are scattered from a block of carbon. What will be the wavelengths of X–rays scattered at 90° ?
  • 0.140 nm
  • 0.142 nm
  • 0.144 nm
  • 0.146 nm
An X-ray tube produces a continuous spectrum of radiation with its shortest wavelength of 45 × 10-2 Å. The maximum energy of a photon in the radiation in eV is (h = 6.62 × 10-34 J-s, c = 3 × 108 ms-1 )
  • 27500
  • 22500
  • 17500
  • 12500
Kα and Kβ , X-rays are emitted when there is a transition of electron between the levels
  • n = 2 to n =1 and n = 3 to n = 1 respectively
  • n = 2 to n =1 and n = 3 to n = 2 respectively
  • n = 3 to n = 2 and n = 4 to n = 2 respectively
  • n = 3 to n = 2 and n = 4 to n = 3 respectively
When two different materials A and B having atomic number Z1 and Z2 are used as the target in Coolidge γ-ray tube at different operating voltage V1and V2 respectively their spectrums are found as below.
Physics-Dual Nature of Radiation and Matter-67355.png
  • V1 > V2 and Z2 > Z1
  • V1 < V2 and Z1 < Z2
  • V1 < V2 and Z1 > Z2
  • V1 > V2 and Z1 < Z2
Hard X–rays for the study of fractures in bones should have a minimum wavelength of 10-11 m. The accelerating voltage for electrons in X–rays machine should be
  • < 124 kV
  • > 124 kV
  • between 60 kV and 70 kV
  • =100 kV
A beam of 35.0 keV electrons strikes a molybdenum target, generating the X–rays. What is the cut–off wavelength?
  • 35.5 pm
  • 40.0 pm
  • 15.95 pm
  • 18.2 pm
An X–rays machine is operated at 40 kV. The short wavelength limit of continuous X-rays will be (h = 6.63×10-34J–s, c = 3×108ms-1, e = 1.6×10-19 C)
  • 0.31 Å
  • 0.62 Å
  • 0.155 Å
  • 0.62 Å
Energy of characteristic X–rays is a consequence of
  • energy of projectile electron
  • thermal energy of target
  • transition in target atoms
  • None of the above
X-rays are used in determining the molecular structure of crystalline because its
  • energy is high
  • it can penetrate the material
  • its wavelength is comparable to interatomic distance
  • its frequency is low
The minimum wavelength of X-rays emitted from X-rays machine operating at an accelerating potential of V volts is

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K α wavelength emitted by an atom of atomic number Z = 11 is λ. Find the atomic number for an atom that emits K α radiation with wavelength 4λ
  • Z = 6
  • Z = 4
  • Z = 11
  • Z = 44
The radiation corresponding to 3 → 2 transition of hydrogen atom falls on a metal surface to produce photoelectrons. These electrons are made to enter a magnetic field of 3 × 10-4 T. If the radius of the largest circular path followed by these electrons is 10.0 mm, the work function of the metal is close to
  • 1.8 eV
  • 1.1 eV
  • 0.8 eV
  • 1.6 eV

Physics-Dual Nature of Radiation and Matter-67361.png
  • h
  • e

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Silver has a work function of 4.7 eV. When ultraviolet light of wavelength 100 nm is incident on it a potential of 7.7 V is required to stop the photoelectrons from reaching the collector plate. How much potential will he required to stop photoelectrons, when light of wavelength 200 nm is incident on it?
  • 2.35 V
  • 15.4 V
  • 3.85 V
  • 1.5 V
The ionisation energy of hydrogen is 13.6 eV. The energy of the photon released when an electron jumps from the first excited state (n =to the ground state of a hydrogen atom is
  • 3.4 eV
  • 4.53 eV
  • 10.2 eV
  • 13.6 eV
What is the ratio of wavelength of a photon and that of an electron (of mass, m) of the same energy (E)?

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    Physics-Dual Nature of Radiation and Matter-67365.png

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A monochromatic light of frequency 3 × 1014 Hz, is produced by a laser, emits the power of 3 × 10-3 W. Find, how many number of photons are emitted per sec?
  • 1.5 × 1016
  • 2.5 × 1016
  • 4.5 × 1016
  • 8.5 × 1016
In a photoelectric effect measurement, the stopping potential for a given metal is found to be V0 volt, when radiation of wavelength is used. If radiation of wavelength 2λ0 is used with the same metal, then the stopping potential (in volt) will be

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  • 2V0

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The work function of a substance is 4.0 eV. The longest wavelength of light that can cause photoelectron emission from this substance is approximately
  • 540 nm
  • 400 nm
  • 310 nm
  • 220 nm
Work function of a metal is 2.1 eV. Which of the waves of the following wavelengths will be able to emit photoelectrons from its surface?
  • 4000 Å , 7500 Å
  • 5500 Å , 6000 Å
  • 4000 Å , 6000 Å
  • None of these
A monochromatic source of light emits photons of frequency 6 × 1014 Hz. The power emitted by the source is 8 × 10-3 W. Calculate the number of photons emitted per sec (take, h = 6.63 × 10-34 J-s)
  • 6 × 1014
  • 4 × 1015
  • 2 × 1016
  • 1 × 1017
If e/m of electron is 1.76 ×1011 C kg-1 and stopping potential is 0.71 V, then the maximum velocity of the photoelectron is
  • 150 km/s
  • 200 km/s
  • 500 km/s
  • 250 km/s
  • 100 km/s
The frequency of a photon having energy 100 eV is (take, h = 6.67 × 10-34 J-s, 1 eV = 1.6 × 10-19 J)
  • 2.4 × 10-16
  • 2.4 × 1016
  • 2.4 × 1017
  • 10.54 × 1016
What is the work function (in eV) of a substance, if photoelectrons are just ejected for a monochromatic light of wavelength λ = 3300 Å ?
  • 3.75
  • 3.25
  • 1.63
  • 0.75
The photoelectric threshold wavelength for silver is λ0. The energy of the electron ejected from the surface of silver by an incident wavelength λ(λ < λ0 ) will be

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An atom of mass M, which is in the state of rest emits a photon of wavelength λ. As a result, the atom will deflect with the kinetic energy equal to (h is Planck's constant)

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  • 2)
    Physics-Dual Nature of Radiation and Matter-67378.png

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Photon and electron are given energy (10-2 J). Wavelengths associated with photon and electron are λph and λel , then correct statement will be
  • λph > λel
  • λph < λel
  • λph = λel

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The surface of a metal is illuminated with the light of 400 nm. The kinetic energy of the ejected photoelectrons was found to be 1.68 eV. The work function of the metal is (hc = 1240 eV-nm)
  • 3.09 eV
  • 1.42 eV
  • 151 eV
  • 1.68 eV
Assertion (A) Photoelectric effect can take place only with an electron bound in the atom.
Reason (R) Electron is a fermion whereas proton is a boson.
  • if both A and R are correct and R is the correct explanation of A
  • If both A and R are correct but R is not the correct explanation of A
  • If A is correct but R is incorrect
  • If A is incorrect but R is correct
A light whose frequency is equal to 6 × 1014 Hz, is incident on a metal whose work function is 2eV. (h = 6.63 ×10-34 J-s, leV =1.6 × 10-19 J ). The maximum energy of the electrons emitted will be
  • 2.49 eV
  • 4.49 eV
  • 0.49 eV
  • 5.49 eV
When a piece of metal is illuminated by a monochromatic light of wavelength λ , then stopping potential is 3Vs. When same surface is illuminated by light of wavelength 2λ , then stopping potential becomes Vs. The value of threshold wavelength for photoelectric emission will be
  • 4λ
  • 8λ

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  • 6λ
The threshold wavelength for photoelectric emission from a material is 4800 Å. Photoelectrons will be emitted from the material. when it is illuminated with light from a
  • 40 W blue lamp
  • 40 W green lamp
  • 100 W red lamp
  • 100 W yellow lamp
  • 1000 W green lamp
The frequency and intensity of a light source are doubled. Consider the following statements
I. Saturation photocurrent remains almost the same.
II. Maximum kinetic energy of the photoelectrons is doubled.
  • Both I and II are true
  • I is true but II is false
  • I is false but II is true
  • Both I and II are false
Monochromatic light of frequency f incident on emitter having threshold frequency f0. The kinetic energy of ejected electron will be
  • hf
  • h ( f – f0 )
  • hf0
  • h ( f + f0 )
In photoelectric effect, the threshold wavelength of sodium is 5000 Å . Find its work function.
(h = 6.6 × 10-34 J-s , c = 3 × 108ms-1 , 1 eV = 1.6 × 10-19 J )
  • 7.5 eV
  • 2.5 eV
  • 10 eV
  • 5.0 eV

Physics-Dual Nature of Radiation and Matter-67384.png
  • λ ≥ λ0
  • λ ≥ 2λ0
  • λ ≤ λ0
  • λ = 4λ0
When radiation is incident on a photoelectron emitter, the stopping potential is found to be 9V. If e/m for the electron is 1.8 × 1011 C kg-1, the maximum velocity of the ejected electron is
  • 6 × 105 ms-1
  • 8 × 105 ms-1
  • 1.8 × 106 ms-1
  • 1.8 × 105 ms-1
A photosensitive material would emit electrons, if excited by photons beyond a threshold. To overcome the threshold, one would increase the
  • voltage applied to the light source
  • intensity of light
  • wavelength of light
  • frequency of light
A photoelectric cell is illuminated by a point source of light 1 m away. When the source is shifted to 2 m then
  • each muted electron carries half the initial energy
  • number of electrons emitted is a quarter of the initial number
  • each emitted electron carries one quarter of the initial energy
  • number of eletrons emitted is half the initial number
The photosensitive surface is receiving light of wavelength 5000 Å at the rate of 10-8 J–s-1 . The number of photons received per sec is
  • 2.5 × 1010
  • 2.5 × 1011
  • 2.5 × 1012
  • 2.5 × 109
When light of wavelength 300 nm, falls on a photoelectric emitter, photoelectrons are liberated. For another emitter, light of wavelength 600 nm is sufficient for liberating photoelectrons. The ratio of the work function of the two emitters is
  • 1 : 2
  • 2: 1
  • 4: 1
  • 1 : 4
Maximum velocity of the photoelectrons emitted by a metal surface is 1.2 × 106ms-1 . Assuming the specific charge of the electron to be 1.8 × 1011C kg-1, the value of the stopping potential in volt will be
  • 2
  • 3
  • 4
  • 6
Which one of the following graph represents the variation of maximum kinetic energy (Ek) of the emitted electrons with frequency v in photoelectric effect correctly ?

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0:0:1


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