JEE Questions for Physics Dual Nature Of Radiation And Matter Quiz 11 - MCQExams.com

According to photon theory of light which of the following physical quantities associated with a photon do not/does not change as it collides with an electron in vacuum?
  • Energy and momentum
  • Speed and momentum
  • Speed only
  • Energy only
Sodium and copper have work functions 2.3 eV and 4.5 eV respectively. Then the ratio of their threshold wavelengths is nearest to
  • 1 : 2
  • 4 : 1
  • 2 : 1
  • 1 : 4
A caesium photocell, with a steady potential difference of 60 V across, is illuminated by a bright point source of light 50 cm away. When the same light is placed 1 m away the photoelectrons emitted from the cell
  • Are one quarter as numerous
  • Are half as numerous
  • Each carry one quarter of their previous momentum
  • Each carry one quarter of their previous energy
The number of photons of wavelength 540 nm emitted per second by an electric bulb of power 100 W is (taking h = 6 × 10–34 J-s)
  • 100
  • 1000
  • 3 × 1020
  • 3 × 1018
Light of frequency 4v0 is incident on the metal of the threshold frequency v0. The maximum kinetic energy of the emitted photoelectrons is
  • 3 hv0
  • 2 hv0

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By photoelectric effect, Einstein, proved

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    Physics-Dual Nature of Radiation and Matter-67846.png

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Two identical photo-cathodes receive light of frequencies f1 and f2. If the velocities of the photo electrons (of mass m) coming out are respectively v1 and v2, then

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    Physics-Dual Nature of Radiation and Matter-67850.png

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Consider the two following statements A and B and identify the correct choice given in the answers;
(A) In photovoltaic cells the photoelectric current produced is not proportional to the intensity of incident light
(B) In gas filled photoemissive cells, the velocity of photoelectrons depends on the wavelength of the incident radiation
  • Both A and B are true
  • Both A and B are false
  • A is true but B is false
  • A is false B is true
When radiation of wavelength λ is incident on a metallic surface, the stopping potential is 4.8 volts. If the same surface is illuminated with radiation of double the wavelength, then the stopping potential becomes 1.6 volts. Then the threshold wavelength for the surface is
  • 2 λ
  • 4 λ
  • 6 λ
  • 8 λ
The frequency and work function of an incident photon are v and ϕ0. If v0 is the threshold frequency then necessary condition for the emission of photo electron is

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  • 2)
    Physics-Dual Nature of Radiation and Matter-67856.png

  • Physics-Dual Nature of Radiation and Matter-67857.png
  • None of these
If the wavelength of light is 4000 Å, then the number of waves in 1 mm length will be
  • 25
  • 0.25
  • 0.25 × 104
  • 25 × 104
If the work function of a photometal is 6.825 eV. Its threshold wavelength will be (c = 3 × 108 m/s)
  • 1200 Å
  • 1800 Å
  • 2400 Å
  • 3600 Å
A photon of energy 8 eV is incident on a metal surface of threshold frequency 1.6 × 1015 Hz, then the maximum kinetic energy of photoelectrons emitted is (h = 6.6 × 10–34Js)
  • 4.8 eV
  • 2.4 eV
  • 1.4 eV
  • 0.8 eV
If the energy of the photon is increased by a factor of 4, then its momentum
  • Does not change
  • Decreases by a factor of 4
  • Increases by a factor of 4
  • Decreases by a factor of 2
Photoelectric effect can be explained by
  • Corpusular theory of light
  • Wave nature of light
  • Bohr's theory
  • Quantum theory of light
The photoelectric effect can be understood on the basis of
  • The principle of superposition
  • The electromagnetic theory of light
  • The special theory of relativity
  • Line spectrum of the atom
Which of one is correct ?
  • E2 = p2c2
  • E2 = p2c
  • E2 = pc2
  • E2 = p2 /c2
If a source of power 4 kW produces 1020 photons/second, the radiation belongs to a part of the spectrum called
  • γ-rays
  • X-rays
  • Ultraviolet rays
  • Microwaves
In an experiment of photoelectric effect the stopping potential was measured to be V1 and V2 volts with incident light of wavelength λ and λ /2 respectively. The relation between V1 and V2 may be
  • V2 < V1
  • V1 < V2 < 2V1
  • V2 = 2V1
  • V2 > 2V1
According to Einstein\'s photoelectric equation, the graph of K.E. of the photoelectron emitted from the metal versus the frequency of the incident radiation gives a straight line graph, whose slope
  • Depends on the intensity of the incident radiation
  • Depends on the nature of the metal and also on the intensity of incident radiation
  • Is same for all metals and independent of the intensity of the incident radiation
  • Depends on the nature of the metal
If m is the mass of an electron and c is the speed of light, the ratio of the wavelength of a photon of energy E to that of the electron of the same energy is

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    Physics-Dual Nature of Radiation and Matter-67867.png

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  • Physics-Dual Nature of Radiation and Matter-67869.png

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If the energy of Kα spectral line of an atom is 59 keV, then the wavelength of Kα line will be
  • 0.20 Å
  • 0.42 Å
  • 0.31 Å
  • 0.62 Å
Which of the following wavelength fall in X-ray region?
  • 10000 Å
  • 1000 Å
  • 1 Å
  • 10–2 Å
In producing X-rays a beam of electrons accelerated by a potential difference V is made to strike a metal target. For what value of V, X-rays will have the lowest wavelength of 0.3094 Å?
  • 10 kV
  • 20 kV
  • 30 kV
  • 40 kV
In radio therapy, X-rays are used to
  • Detect bone fractures
  • Treat cancer by controlled exposure
  • Detect heart diseases
  • Detect fault in radio receiving circuits
Hydrogen atom does not emit X-rays because
  • Its energy levels are too close to each other
  • Its energy levels are too apart
  • It is too small in size
  • It has a single electron
X-rays were discovered by
  • Becquerel
  • Roentgen
  • Marie Curie
  • Von Laue
X-rays are
  • Stream of electrons
  • Stream of positively charged particles
  • Electromagnetic radiations of high frequency
  • Stream of uncharged particles
Which one of the following statement is WRONG in the context of X-rays generated from a X-ray tube
  • Wavelength of characteristic X-rays decreases when the atomic number of the target increases
  • Cut-off wavelength of the continuous X-rays depends on the atomic number of the target
  • Intensity of the characteristic X-rays depends on the electrical power given to the X-ray tube
  • Cut-off wavelength of the continuous X-rays depends on the energy of the electrons in the X-ray tube
The characteristic X-ray radiation is emitted, when
  • The electrons are accelerated to a fixed energy
  • The source of electrons emits a monoenergetic beam
  • The bombarding electrons knock out electrons from the inner shell of the target atoms and one of the outer electrons falls into this vacancy
  • The valence electrons in the target atoms are removed as a result of the collision
Molybdenum is used as a target element for production of X-ray because it is
  • A heavy element and can easily absorb high velocity electrons
  • A heavy element with a high melting point
  • An element having high termal conductivity
  • Heavy and can easily deflect electrons
Mosley\'s law relates the frequencies of line x-rays with the following characteristics of the target element
  • Its density
  • Its atomic weight
  • Its atomic number
  • Interplaner spacing of the atomic planes
According to Moseley\'s law of X-rays the frequency (v) of a particular characteristic X-ray and the atomic number (Z) of the element depend on each other as

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    Physics-Dual Nature of Radiation and Matter-67877.png

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Electrons with de-Broglie wavelength λ fall on the target in an X-ray tube. The cut-off wavelength of the emitted X-rays is

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    Physics-Dual Nature of Radiation and Matter-67882.png

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  • Physics-Dual Nature of Radiation and Matter-67884.png
If f1, f2 and f3 are the frequencies of corresponding Kα, Kβ and Lα X-rays of an element, then

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  • 2)
    Physics-Dual Nature of Radiation and Matter-67889.png

  • Physics-Dual Nature of Radiation and Matter-67890.png

  • Physics-Dual Nature of Radiation and Matter-67891.png
The longest wavelength that can be analysed by a sodium chloride crystal of spacing d= 2.82 Å in the second order is
  • 2.82 Å
  • 5.64 Å
  • 8.46 Å
  • 11.28 Å
A direct X-ray photograph of the intestines is not generally taken by the radiologists because
  • Intestines would burst on exposure to X-rays
  • The X-rays would not pass through the intestines
  • The X-rays will pass through the intestines without causing a good shadow for any useful diagnosis
  • A very small exposure of X-rays causes cancer in the intestines
In X-ray experiment Kα, Kβ denotes
  • Characteristic
  • Continuous wavelength
  • α, β-emission respectively
  • None of the above
The wavelength of Kα line in copper is 1.54 Å. The ionisation energy of K electron in copper in Joule is
  • 11.2 × 10–27
  • 12.9 × 10–16
  • 1.7 × 10–15
  • 10 × 10–16
Absorption of X-ray is maximum in which of the following different sheets?
  • Copper
  • Gold
  • Beryllium
  • Lead
The X-ray beam coming from an X-ray tube will be
  • Monochromatic
  • Having all wavelengths smaller than a certain maximum wavelength
  • Having all wavelengths larger than a certain minimum wavelength
  • Having all wavelengths lying between a minimum and a maximum wavelength
The continuous X-rays spectrum produced by an X-ray machine at constant voltage has
  • A maximum wavelength
  • A minimum wavelength
  • A single wavelength
  • A minimum frequency
If λ1 and λ2 are the wavelengths of characteristic X-rays and gamma rays respectively, then the relation between them is

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    Physics-Dual Nature of Radiation and Matter-67896.png

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  • Physics-Dual Nature of Radiation and Matter-67898.png
The wavelength λ of the Kα line of characteristic X-ray spectra varies with atomic number approximately

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  • 2)
    Physics-Dual Nature of Radiation and Matter-67900.png

  • Physics-Dual Nature of Radiation and Matter-67901.png

  • Physics-Dual Nature of Radiation and Matter-67902.png
An X-ray tube with a copper target emits Kα line of wavelength 1.50 Å. What should be the minimum voltage through which electrons are to be accelerated to produce this wavelength of X-rays
(h = 6.63 × 10–34 J-s, c = 3 × 108 m/s)
  • 8280 V
  • 828 V
  • 82800 V
  • 8.28 V
Which of the following is accompanied by the characteristic X-ray emission?
  • α-particle emission
  • Electron emission
  • Positron emission
  • K-electron capture
X-rays are known to be electromagnetic radiations. Therefore the X-ray photon has
  • Electric charge
  • Magnetic moment
  • Both electric charge and magnetic moment
  • Neither electric charge nor magnetic moment
X-rays of which of the following wavelengths are hardest?
  • 4 Å
  • 1 Å
  • 0.1 Å
  • 2 Å
X-rays region lies between
  • Short radiowave and visible region
  • Visible and ultraviolet region
  • Gamma rays and ultraviolet region
  • Short radiowave and long radiowave
The structure of solid crystals in investigated by using
  • Cosmic rays
  • X-rays
  • Infrared radiations
  • γ-rays
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