JEE Questions for Physics Dual Nature Of Radiation And Matter Quiz 2 - MCQExams.com

When intensity of incident light increases
  • photo current increases
  • photo current decreases
  • kinetic energy of emitted photoelectrons increases
  • kinetic energy of emitted photoelectrons decreases
In photoelectric effect, the electrons are ejected from metals if the incident light has a certain minimum
  • wavelength
  • frequency
  • amplitude
  • angle of incidence
A light having wavelength 300 nm falls on a metal surface. Work function of metal is 2.54 eV. What is stopping potential ?
  • 2.3 V
  • 2.59 V
  • 1.60 V
  • 1.29 V
The time taken by a photoelectron to come out after the photon strikes is approximately
  • 10-4 s
  • 10-10 s
  • 10-16 s
  • 10-1 s
Light of frequency v falls on material of threshold frequency v0 . Maximum kinetic energy of emitted electron is proportional to
  • v - v0
  • v

  • Physics-Dual Nature of Radiation and Matter-67297.png
  • v0
Light of energy 2.0 eV falls on a metal of work function 1.4 eV. The stopping potential is
  • 0.6 V
  • 2.0 V
  • 3.4 V
  • 1.4 V
When a big drop of water is formed from n small drops of water, the energy loss is 3E, where E is the energy of the bigger drop. If R is the radius of the bigger drop and r is the radius of the smaller drop, then number of smaller drops (n) is

  • Physics-Dual Nature of Radiation and Matter-67299.png
  • 2)
    Physics-Dual Nature of Radiation and Matter-67300.png

  • Physics-Dual Nature of Radiation and Matter-67301.png

  • Physics-Dual Nature of Radiation and Matter-67302.png
The anode voltage of a photocell is kept fixed. The wavelength λ of the light falling on the cathode is gradually changed. The plate current I of photocell varies as follows:

  • Physics-Dual Nature of Radiation and Matter-67303.png
  • 2)
    Physics-Dual Nature of Radiation and Matter-67304.png

  • Physics-Dual Nature of Radiation and Matter-67305.png

  • Physics-Dual Nature of Radiation and Matter-67306.png
Assertion (A) If the accelerating potential of an electron is doubled, then its velocity becomes 1.4 times.
Reason (R) It will move on a circular path with same velocity.
  • 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.
When a cathode ray tube is operated at 2912 V, the velocity of electrons is 3.2 × 107 m/s. Find the velocity of cathode ray if the tube is operated at 5824 V.
  • 2.4 × 107 m/s
  • 5.2 × 107 m/s
  • 4.525 × 107 m/s
  • 2.4 × 106 m/s
An α-particle of mass 6.4 × 10-27 Kg and charge 3.2 × 10-19C is situated in a uniform electric field of 1.6 × 105Vm-1 . The velocity of the particle at the end of 2 × 10-2m path when it starts from rest is
  • 2√3 × 105 ms-1
  • 8 × 105 ms-1
  • 16 × 105 ms-1
  • 4√2 × 105 ms-1
The temperature at which protons in proton gas would have enough energy to overcome Coulomb barrier of 4.14 × 10 -14 Js is ( Boltzmann constant = 1.38 × 10 -23 JK -1 )
  • 2 × 109 K
  • 109 K
  • 6 × 109 K
  • 3 × 109 K
  • 4.5 × 109 K
Millikan's oil drop experiment established that
  • electric charge depends on velocity
  • specific charge of electron is 1.76 × 1011 CKg -1
  • electron has wave nature
  • electric charge is quantised
  • electron has particle nature
In a cathode ray oscillograph, the focusing of beam on the screen is achieved by
  • convex lenses
  • magnetic yield
  • electric potential
  • All of the above
A strong argument for the particle nature of cathode rays is that they
  • produce fluorescence
  • travel through vacuum
  • get deflected by electric and magnetic fields
  • cast shadow
Electron of mass m and charge e in external field E experiences acceleration

  • Physics-Dual Nature of Radiation and Matter-67310.png
  • 2)
    Physics-Dual Nature of Radiation and Matter-67311.png

  • Physics-Dual Nature of Radiation and Matter-67312.png

  • Physics-Dual Nature of Radiation and Matter-67313.png
The specific charge of a proton is 9.6 × 107 C kg-1 . The specific charge of an α -particle will be
  • 9.6 × 107 C kg-1
  • 19.2 × 107 C kg-1
  • 4.8 × 107 C kg-1
  • 2.4 × 107 C kg-1

Physics-Dual Nature of Radiation and Matter-67314.png
  • 1
  • zero
  • ge / gm
  • gm / ge
A charged oil drop is suspended in uniform field of 3 × 104 Vm-1,so that it neither falls nor rises. The charge on the drop will be (take, the mass of the charge = 9.9 × 10 -15 kg and g = 10 ms -2 )
  • 3.3 × 10 -18 C
  • 3.2 × 10 -18 C
  • 1.6 × 10 -18 C
  • 4.8 × 10 -18 C
Cathode rays of velocity 106ms -1 describe an approximate circular path of radius 1 m in an electric field 300 Vcm-1. If the velocity of the cathode rays are doubled. The value of electric field so that the rays describe the same circular path, will he
  • 2400 V cm-1
  • 600 V cm-1
  • 1200 V cm-1
  • 12000 V cm-1
When a high energy UV photon beam enters an electric field, it will be
  • accelerated
  • retarded
  • undeflected
  • None of these
An α-particle of energy 5 MeV is scattered through 180° by a fixed uranium nucleus. The distance of the closest approach is of the order of
  • 1 Å
  • 10 -10 cm
  • 10 -12 cm
  • 10 -15 cm
In a region, steady and uniform electric and magnetic fields are present. These two fields are parallel to each other. A charged particle is released from rest in this region. The path of the particle will be a
  • helix
  • straight line
  • ellipse
  • circle
The matertial used lot making thermionic cathode must have
  • low work function and low melting point
  • low work function and high melting point
  • high work function and high melting point
  • high work function and low melting point
J J Thomson's cathode rays tube experiment demonstrated that
  • cathode rays are streams of negatively charged ions
  • all the mass of an atom is essentially in the nucleus
  • the e/m of electrons is much greater than the e/m of protons
  • the e/m ratio of the cathode ray particles changes when a different gas is placed in the discharge tube
A oil drop having a mass 4.8 × 10-10 g and charge 2.4 × 10-18 C stands still between two charged horizontal plates separated by a distance of 1 cm. If now the polarity of the plates is changed, instantaneous acceleration of the drop is (take, g =10 ms-2)
  • 5 ms -2
  • 10 ms -2
  • 15 ms -2
  • 20 ms -2
In Millikan's oil drop experiment, an oil drop of mass 16 × 10 -6 kg is balanced by an electric field of 10 6 Vm -1 . The charge in coulomb on the drop is (assume , g =10 ms-2)
  • 6.2 × 10 -11
  • 16 × 10 -9
  • 16 × 10 -11
  • 16 × 10 -13
A uniform electric field and a uniform magnetic field are acting along the same direction in a certain region. If an electron is projected along the direction of the fields with a certain velocity, then
  • its velocity will decrease
  • its velocity will increase
  • it will turn towards right of direction of motion
  • it will turn towards left of direction of motion
The figure shows the path of a positively charged particle 1 through a rectangular region of uniform electric field as shown in the figure. What is the direction of electric field and the direction of deflection of particles 2, 3 and 4 ?
Physics-Dual Nature of Radiation and Matter-67317.png
  • Top, down, top, down
  • Top, down, down, top
  • Down, top, top, down
  • Down, top, down, down
If an electron moves from rest a point at which potential is 50 V to another point at which potential is 70 V, then its kinetic energy in the final state will be
  • 3.2 × 10 -20 J
  • 3.2 × 10 -18 J
  • 3.2 × 10 -19 J
  • zero
If the distance of 100 W lamp is increased from a photocell, the saturation current i in the photocell varies with the distance d as
  • i ∝ d 2
  • i ∝d
  • i ∝ 1 / d
  • i ∝ 1 / d 2
The energy of a photon is equal to the kinetic energy of a proton. If λ1 is the de-Broglie wavelength of a proton, λ2 the wavelength associated with the proton and if the energy of the photon is E, then (λ1 / λ2 ) is proportional to
  • E 4
  • E 1/2
  • E 2
  • E
In a hydrogen like atom, electron makes transition from an energy level with quantum number n to another with quantum number (n – 1). If n >> 1, the frequency of radiation emitted is proportional to

  • Physics-Dual Nature of Radiation and Matter-67318.png
  • 2)
    Physics-Dual Nature of Radiation and Matter-67319.png

  • Physics-Dual Nature of Radiation and Matter-67320.png

  • Physics-Dual Nature of Radiation and Matter-67321.png
The work functions of silver and sodium are 4.6 and 2.3 eV, respectively. The ratio of the slope of the stopping potential versus frequency plot for silver to that of sodium is
  • 4
  • 3
  • 1
  • 7

Physics-Dual Nature of Radiation and Matter-67322.png

  • Physics-Dual Nature of Radiation and Matter-67323.png
  • 2)
    Physics-Dual Nature of Radiation and Matter-67324.png

  • Physics-Dual Nature of Radiation and Matter-67325.png

  • Physics-Dual Nature of Radiation and Matter-67326.png
The de-Broglie wavelength of an electron moving with a velocity c / 2 (c = velocity of light in vacuum) is equal to the wavelength of a photon. The ratio of the kinetic energies of electron and photon is
  • 1 : 4
  • 1 : 2
  • 1 : 1
  • 2 : 1
An electron and a proton are moving in the same direction with same kinetic energy. The ratio of the de-Broglie wavelength associated with these particles is

  • Physics-Dual Nature of Radiation and Matter-67327.png
  • 2)
    Physics-Dual Nature of Radiation and Matter-67328.png

  • Physics-Dual Nature of Radiation and Matter-67329.png

  • Physics-Dual Nature of Radiation and Matter-67330.png
An electron is accelerated under a potential difference of 182 V. The maximum velocity of electron will be (charge of an electron is 1.6 × 10-19 C and its mass is 9.1 × 10-31 kg)
  • 5.65 × 106 m/s
  • 4 × 106 m/s
  • 8 × 106 m/s
  • 16 × 106 m/s

Physics-Dual Nature of Radiation and Matter-67333.png
  • 3
  • 4
  • 2
  • 4.5
The de-Broglie wavelength of the electron in the ground state of the hydrogen atom is (radius of the first orbit of hydrogen atom = 0.53 Å)
  • 1.67 Å
  • 3.33 Å
  • 1.06 Å
  • 0.53 Å
If an electron and a photon propagates in the form of waves having the same wavelength, it implies that they have the same
  • energy
  • momentum
  • velocity
  • angular momentum
If the linear momentum of a particle is 2.2 × 10 4 kg-ms-1, then what will be its de-Broglie wavelength ?
(take, h = 6.6 × 10 -34 J-s)
  • 3 × 10 -29 m
  • 3 × 10 -29 nm
  • 6 × 10 -29 m
  • 6 × 10 -29 nm
Which of the following figures represents the variation of particle momentum and associated de-Broglie wavelength ?

  • Physics-Dual Nature of Radiation and Matter-67335.png
  • 2)
    Physics-Dual Nature of Radiation and Matter-67336.png

  • Physics-Dual Nature of Radiation and Matter-67337.png

  • Physics-Dual Nature of Radiation and Matter-67338.png
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

  • Physics-Dual Nature of Radiation and Matter-67339.png
  • 2)
    Physics-Dual Nature of Radiation and Matter-67340.png

  • Physics-Dual Nature of Radiation and Matter-67341.png
  • λ0 = λ
Monochromatic light of wavelength 3000 Å is incident on a surface area 4 cm2. If intensity of light is 150 mW m-2 then, rate at which photons strike the target is
  • 3 × 1010 s-1
  • 9 × 1013 s-1
  • 7 × 1015 s-1
  • 6 × 1019 s-1
One electron and one proton is accelerated by equal potential. Ratio in their de-Broglie wavelengths is
  • 1
  • 2)
    Physics-Dual Nature of Radiation and Matter-67342.png

  • Physics-Dual Nature of Radiation and Matter-67343.png

  • Physics-Dual Nature of Radiation and Matter-67344.png
The de-Broglie wavelength of a proton (charge = 1.6 × 10-19 C, mass = 1.6 × 10-27 kg), accelerated through a potential difference of 1 kV is
  • 600 Å
  • 0.9 × 10-12 m
  • 7 Å
  • 0.9 nm
Monochromatic light of frequency 6.0 × 104 Hz is produced by a laser. The power emitted is 2 × 10-3W. The number of photons emitted, on the average, by the source per second is
  • 5 × 1015
  • 5 × 1016
  • 5 × 1017
  • 5 × 1014
If nR and nV denote the number of photons emitted by a red bulb and violet bulb of equal power in a given time, then
  • nR = nV
  • nR > nV
  • nR < nV
  • nR ≥ nV
The radio transmitter operates on a wavelength of 1500 m at a power of 400 kW. The energy of radio photon (in joule) is
  • 1.32 × 10 -24 J
  • 1.32 × 10 -28 J
  • 1.32 × 10 -26 J
  • 1.32 × 10 -32 J
0:0:1


Answered Not Answered Not Visited Correct : 0 Incorrect : 0

Practice Physics Quiz Questions and Answers