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CBSE Questions for Class 12 Medical Physics Dual Nature Of Radiation And Matter Quiz 9 - MCQExams.com

Which of the following figures represent the variation of particle momentum and the associated de-Broglie wavelength?
The de Broglie wavelength λ associated with a  proton increases by 25%. If its momentum is decreased by p0. The initial  momentum was:
  • 4p0
  • p04
  • 5p0
  • p05
A monochromatic beam of electromagnetic radiation has an intensity of 1W/m2 . Then the average number of photons per m3 for  a 10MeV γ ray is ? 
  • 4166
  • 3000
  • 5000
  • 2083
When light of intensity 1 W/m2 and wavelength 5×107m is incident on a surface, it is completely absorbed by the surface. If 100 photos emit one electron and area of the surface is 1 cm2, then the photoelectric current will be
  • 2 mA
  • 0.4 μA
  • 4.0 mA
  • 4 μA
The De-Broglie wavelength associated with electrons revolving round the nucleus in a hydrogen atom in ground state, will be-
  • 0.3 A
  • 3.3 A
  • 6.62 A
  • 10 A
The de Broglie wavelength corresponding to the root-mean-square velocity of hydrogen molecules at temperature 20o C is 
  • 3.3Ao
  • 1.04Ao
  • 126Ao
  • 34Ao
The ratio of dBroglie wavelength of molecular of hydrogen and oxygen kept in two vessels separately at 27oC and 127oC respectively is:
  • 43
  • 332
  • 83
  • 18
When a point source of light is at a distance of 50cm from a photoelectric cell, the cut -off voltage is found to be V0.If the same source is placed at a distance of 1m from the cell,then the cut -off voltage will be:
  • V0/4
  • V0/2
  • V0
  • 2V0
A proton is accelerated through 225V. Its de Brogile wavelength is:
  • 1.91pm
  • 0.2pm
  • 3pm
  • 0.4nm
 what is the angular momentum of an electron of debroglie wavelength λ? given r is the radius of orbit.
  • rhλ
  • 2rhλ
  • 3rhλ
  • 4rhλ
According to de Broglie, wavelength of electron in second orbit is 109 meter. Then the circumference of orbit is :-
  • 109
  • 2×109
  • 3×109
  • 4×109
Threshold wavelength of tungsten is 2300 angstrom. If ultraviolet light of wavelength 1800 angstrom is incident on it, then the maximum kinetic energy of photoelectrons would be ?
  • 1.5 eV
  • 2.5eV
  • 3.0 eV
  • 5.0eV
A particle is dropped from a height H. The de-Broglie wavelength of the particle as a function of height is proportional to
  • H
  • H12
  • Ho
  • H12
A photon and an electron both have wavelength 1Ao. The ratio of energy of photon to that of electron is
  • 1
  • 0.012
  • 82.7
  • 1010
The de-Broglie wavelength of an electron is the same as the wavelength of a photon. The K.E of photon is x times the K.E of the electron,then x is (m-mass electron ,h- planck's constant,c-velocity of light)
  • hc2λm
  • 2mλch
  • 2λchm
  • 2λmch
The radio of deBroglie wavelengths of a proton and an alpha particle of same energy is
  • 1
  • 2
  • 4
  • 0.25
A chlorine molecule with an initial velocity of 600ms1 absorbs a photon of wavelength 350 nm and is then dissociated into two chlorine atoms. One of the atoms is detected moving perpendicular to the initial direction of the molecule and having a velocity of 1600ms1. The binding energy of the molecule is (approx)? [Neglect the momentum of the absorbed photon. The relative atomic mass of chlorine is 35]
  • 3.36×1017J
  • 3.36×1019J
  • 3.36×1021J
  • 3.36×1028J
Electron has energy of 100 eV what will be its wavelength
  • 1.2˚A
  • 10˚A
  • 100˚A
  • 1˚A
The de Broglie wavelength of an electron moving with a velocity 1.5×108ms1 is equal to that a photon. The ratio of the kinetic energy of the electron to the that of the photon is 
  • 2
  • 4
  • 12
  • 14
A photon and an electron both have wavelength 1˚A. The ratio of energy of photon to that of electron is 
  • 1
  • 0.012
  • 82.7
  • 1010
If the rest mass of an electron or positron is 0.51 MeV, then the kinetic energy of each particle, in the electron-positron pair produced by a γphoton of 2.42 MeV, will be ?
  • 0.3 MeV
  • 1.9 MeV
  • 0.7 MeV
  • 1.5 MeV
An α particle is moving in a circular path of radius in the presence of magnetic field B. The de-Broglie wavelength associated with the particle will be (qchargeonαparticle)
  • hrqB
  • hBqr
  • hqBr
  • hr2qB
A photon and an electron have equal energy E. λphoton×λelectron is proportional to:
  • E32
  • 1E
  • 1E
  • Does not depend upon E.
De-Broglie wavelength associated with thermal neutrons at room temperature of 270C is :
  • 1.452×1010m
  • 2.57×1010
  • 0.452×1010m
  • 3.452×1010m
A particle of mass M at rest decays into particles of masses m1 and m2 having non -zero velocities. The ratio of the de broglie wavelengths of the particles λ1/λ2 is :
  • m1/m2
  • m2/m1
  • 1
  • m1.m2
The threshold frequency for a photosenstive metal is 7×1013Hz. If light of frequency 1014Hz is incident on this metal, then maximum kinetic energy of emitted electron is?
  • 4×1020J
  • 8×1020J
  • 2×1020J
  • 1020J
The ratio of wavelength of deutron and proton accelerated through the same potential difference will be-
  • 12
  • 21
  • 12
  • 21
A source S1 is producing 1015 photons per second of wavelength 5000 Ao . Another source S2 is producing 1.02×1015 photons per second of wavelength 5100 Ao .Then, (power of S2)(power of S1) is equal to
  • 0.98
  • 1.00
  • 1.02
  • 1.04
If Bohr radius is r0, the corresponding de Broglie wavelength of the electron is 
  • (2πro)
  • (ro2π)
  • (12πro)
  • 2πro
Energy of a photon having wave number 1.00cm1 is 
  • 6.62×1034 J
  • 1.99×1023 J
  • 6.62×1032 J
  • 6.62×1036 J
Five elements A,B,C,DandE have work functions 1.2eV,2.4eV,3.6eV,4.8eVand6.8eV respectively. If light of wavelength 4000A is allowed to fall on these elements, then photoelectrons are emitted by
  • A,BandC
  • A,B,C,DandE
  • AandB
  • OnlyE
An electron beam has a kinetic energy equal to 100 eV. Find its wavelength associated with a beam, if mass of electron is 9.1×1031 kg and  1 eV =1.6×1019J. (Planck's constant is 6.6×1034Js)
  • 24.6Ao
  • 0.12Ao
  • 1.2Ao
  • 6.3Ao
Photoeelectric work-function of a metal is 1eV. Light of wavelength λ=3000˚A falls on it. The photoelectrons come out with maximum velocity:
  • 10m/s
  • 103m/s
  • 104m/s
  • 106m/s
K1 and K2 are the maximum kinetic energies of the photo electrons emitted when light of wave lengths λ1 and λ2 respectively are incident on a metallic surface. If λ1=3λ2 then
  • K1>K33
  • K1<K23
  • K1>3K2
  • K2=3K1
When an electron de-excited back from (n+1)th state to nth state in a hydrogen like atoms, wavelength of radiation emitted is λ1(n>>1). In the same atom de-broglies wavelength associated with an electron in nth state is λ2. Then λ1λ2 is proportional to
  • 1n
  • n
  • n2
  • n3
When light is incident on surface, photo electrons are emitted. For photoelectrons:
  • The value of kinetic energy is same for all
  • Maximum kinetic energy do not depend on the
    wave length of incident light
  • The value of kinetic energy is equal to or less
    than a maximum kinetic energy
  • None of the above
The ratio of de-Broglie wavelengths of molecules of hydrogen and helium Which are at temperature 27oC and 127oC respectively is 
  • 12
  • 38
  • 83
  • 1
The velocity of photons is proportional to (where v= frequency) 
  • 1v
  • v2
  • v0
  • v
If E1,E2,E3 and E4 the respectively kinetic energies of electron, decuteron proton and neutron having same de-Broglic wavelength, identity the correct in which those value would increase,
  • E2,E4,E3,E1
  • E1,E3,E4,E2
  • E2,E4,E1,E3
  • E3,E1,E2,E4
Find the maximum KE of photo electrons liberated from the surface of lithium by electron magnetic radiation whose electric component varies with time as ε=a(1+cosωt)cosω0t where a is a constant (ω2π)=6×1014s1 and (ω02π)=0.66×1014s1, work function of lithium =2.39 eV  
  • 0.72 eV
  • 0.36 eV
  • 0.603 eV
  • 0.99 eV
A hydrogen atom emits a photon corresponding to an electron transition from n =5 to n=The recoil speed of hydrogen atom is almost  (mass of proton = 1.6×1027kg)
  • 10 ms1
  • 2×102 ms1
  • 4 ms1
  • 8×102 ms1
If the debroglie wave-length of He at 927oC is λ then de-brolie wave-length of CH4(g) at 27oC will be
  • λ
  • λ2
  • λ4
  • 2λ
The wavelength λe of an electron and λp of a photon of same energy E are related by
  • λpλ2e
  • λpλe
  • λpλe
  • λp1λe
An electron is moving in 2nd excited orbit of H-atom Radius of orbit in terms of de-Broglie wavelength λ of electron can be given as
  • λπ
  • 2λπ
  • 3λ2π
  • λ2π
The work function of a metal is 1.84 eV. If the wavelength of incident photon is 4000˚A, Then the approximate maximum kinetic energy of emitted photoelectron will be 
  • 1.25 eV
  • 3.1 eV
  • 0.58 eV
  • 1.8 eV
The debroglie wavelength of photoelectrons is 1˚A. Its accelerating potential is :
  • 150 V
  • 15.3 V
  • 12.3 V
  • 13.6 V
A parallel beam of uniform, monochromatic light of wavelength 2640 oA has an intensity of 100 W/m2. The number of photons in 1 mm3 of this radiation are -
  • 266
  • 335
  • 442
  • 555
The momentum of a photon is 2×1016 gm-cm/sec. Its energy is
  • 0.61×1026 erg
  • 2.0×1026 erg
  • 6×106 erg
  • 6×108 erg
The de Broglie wavelength of a gas molecule at a temperature T K is:
  • h3mKT
  • h3mKT
  • h2mKT
  • 2mKT
A particle of mass m kg and charge q coulomb is accelerated from rest through V volt: then the de-Broglie wavelength λ associated with it is given by 
  • λ=hmV
  • λ=h2mq
  • λ=h2mqV
  • λ=h2mV
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