Processing math: 7%

CBSE Questions for Class 12 Medical Physics Dual Nature Of Radiation And Matter Quiz 4 - MCQExams.com

The de Broglie wavelength of an electron which falls through a p.d. of 10,000V is
  • 1.227 A0
  • 12.27 A0
  • 0.1227 A0
  • 2.454 A0

A proton has kinetic energy E=100keV which is equal to that of a photon. The wavelength of photon is λ2 and that of proton is λ1. The ratio of λ1/λ2 is proportional to
  • E2
  • E1/2
  • E1
  • E1/2
The wavelength λe of an electron and λp of a photon of same energy E are related by -
  • λp λ2e
  • λp λe
  • λp λe
  • λp 1λe
The hydrogen atom emits a photon of 656.3nm line. The momentum of the photon associated with it is
  • 10^{-27}kgms^{-1}
  • 10^{-23}kgms^{-1}
  • 10^{-18}kgms^{-1}
  • 10^{-15}kgms^{-1}
The figure shows a plot of photo current versus anode potential for a photo sensitive surface for three different radiations. Which one of the following is a correct statement ?


71421_0702913c909b4e15a9268e48e3d7c0ed.png
  • Curves (b) and (c) represent incident radiations same frequencies having same

    intensity.
  • Curves (a) and (b) represent incident radiations of different frequencies and

    different intensities
  • Curves (a) and (b) represent incident radiations of same frequencies but of

    different intensities
  • Curves (b) and (c) represent incident radiations of different frequencies and

    different intensities
Monochromatic light of frequency 6.0\times 10^{14} Hz is produced by a laser. The power emitted is 2\times 10^{-3}W. The number of photons emitted, on the average, by the source per second is:
  • 5\times 10^{14}
  • 5\times 10^{15}
  • 5\times 10^{16}
  • 5\times 10^{17}
The de Broglie wavelength of a neutron when its kinetic energy is K is \lambda .What will be its  wavelength when its kinetic energy is 4K ?
  • \dfrac{\lambda}{4}
  • \dfrac{\lambda}{2}
  • 2\lambda
  • 4\lambda
The de Broglie wavelength associated with an electron of velocity 0.3c and rest mass 9.1 \times 10^{-31}kg is
  • 7.68\times 10^{-10}m
  • 7.68\times 10^{-12}m
  • 5.7\times 10^{-12}m
  • 9.1\times 10^{-12}m
A source S_{1} is producing 10^{15} photons per second of wavelength 5000\dot{a} . Another sorce S_{2} is producing 1.02 \times 10^{15} photons per second of wavelength 5100\dot{A} .Then, (power of S_{2})/(power of S_{1}) is equal to
  • 1.00
  • 1.02
  • 1.04
  • 0.98
The photoelectric work function for a metal surface is 4.125 eV. The cut-off wavelength for this surface is:
  • 4125 A^o
  • 3000 A^o
  • 6000 A^o
  • 2062 A^o
A beam of light of wavelength \lambda is incident on a mirror at an angle \theta. Find the change in momentum of the photon after reflection.
  • 2 \dfrac{h}{\lambda}sin \theta
  • \dfrac{h}{\lambda} cos \theta
  • 2 \dfrac{h}{\lambda}cos \theta
  • none of these
Mass of moving photon is
  • \frac {hv}{c^2}
  • \frac {hv}{c}
  • hv
  • Zero
The momentum of a photon having energy E is
  • \frac {E}{c}
  • \frac {E}{c^2}
  • \frac {E}{h}
  • Zero
A Photoelectric cell converts
  • Light energy into electrical eneregy
  • Light energy into sound energy
  • Electric energy into light energy
  • Light energy into heat energy
When light is incident on a surface, photoelectrons are emitted.
For those photoelectrons:
  • The value of kinetic energy is same
  • Kinetic energy does not depend on the wave length of incident light
  • The value of kinetic energy is equal to or less than a maximum energy
  • None of the above
In a photoelectric effect, the anode potential is plotted against the plate current
73339.jpg
  • A and B will have different intensities while B and C will have different frequencies
  • B and C will have different intensities while A and C will have different frequencies
  • A and B will have different intensities while A and C will have equal frequencies
  • A and B will have equal intensities while B and C will have different frequencies
Rest mass of a photon is
  • \frac {hv}{c^2}
  • \frac {hv}{c}
  • hv
  • zero
The photoelectric effect is described as the ejection of electrons from the surface of a metal when
  • It is heated to a high temperature
  • Light of suitable frequency falls on it
  • Electrons of suitable velocity impinge on it
  • It is placed in a strong magnetic field
Which of the following systems may be adequately described by classical physics?
  • Motion of a cricket ball
  • Motion of dust particle
  • A hydrogen atom
  • A neutron changing to a proton
A point of source of 6 watts emits monochromatic light of wavelength 5000\dot A. The number of photons striking normally per second per unit area of the surface distant 5 m from the source will be
  • 4.82
  • 4.82 \space \times \space 10^{-4}
  • 4.82 \space \times \space 10^{-6}
  • 4.82 \space \times \space 10^{16}
A 40 watt bulb converts 6% of its power to red light (wavelength 6500 \dot{A}). The number of red lights photons emitted by the bulb per second is
  • 100
  • 4 \times 10^{18}
  • 8 \times 10^{18}
  • 13 \times 10^{18}
A radio station emits 10kW power of 90.8 MHz. Find the number of photons emitted per second
  • 1.6 \times \displaystyle 10^{28}
  • \displaystyle 1.6\times 10^{29}
  • \displaystyle 1.6\times 10^{30}
  • \displaystyle 1.6\times 10^{32}
A laser used to weld detached retinas emits light with a wavelength of 652  \displaystyle nm in pulses that are of 20  \displaystyle ms duration. The average power during each pulse is 0.6 \displaystyle W. Find the energy in each pulse in \displaystyle eV and in a single photon.
  • \displaystyle 7.5\times 10^{15} eV, 1.9 eV
  • \displaystyle 7.5\times 10^{15} eV, 1.19 eV
  • \displaystyle 7.5\times 10^{16} eV, 0.19 eV
  • \displaystyle 7.5\times 10^{16} eV, 1.9 eV
A TV center transmits 10 kilowatt of power at 150 MHz. The energy of a photon of electromagnetic wave is
  • 6\space \times 10^{-7} \space J
  • 6\space \times 10^{-7} \space eV
  • 6\space \times 10^{-17} \space J
  • 6\space \times 10^{-17} \space eV
The energy of a photon of wavelength 6000\dot A in eV will be
  • 1.06 eV
  • 0.206 eV
  • 2.06 eV
  • 20 eV
A. The energy E and momentum p of a photon are related as p=\dfrac{E}{c}.

R. The photon behaves as a particle.
  • A and R are both correct and R is correct explanation of A
  • A and R are correct but R is not correct explanation of A
  • A is correct but R is false
  • Both A and R are false
If a proton and an electron have the same de Broglie wavelength, the ratio of the velocity of proton to the velocity of electron will be nearly
  • 1
  • 1840
  • \displaystyle\dfrac{1}{1840}
  • 44
The hydrogen atom emits a photon of 656.3 nm line. Find the momentum of the photon associated with it.
  • 10^{-27} kg ms^{-1}
  • 10^{-23} kg ms^{-1}
  • 10^{-25} kg ms^{-1}
  • none of these
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 initial energy.
  • Twice the initial energy.
  • Thrice the initial energy.
The wavelength associated with 1 MeV proton is
  • 28.6 pm
  • 2.86 pm
  • 2.86 fm
  • 28.6 fm
The minimum energy required to dissociate Ag Br bond in 0.6 eV. A photographic flim is coated with a sliver bromide layer. Find the maximum wavelength whose signature can be recorded on the film
  • 207 nm
  • 702 nm
  • 207 A^{\circ}
  • 2070 nm
Find photon energy in eV
  • 1.04 eV
  • 1.14 eV
  • 1.72 eV
  • 1.28 eV
Find the wavelength of 100 eV electron
  • 1.227 \displaystyle A^{\circ}
  • 1.72 \displaystyle A^{\circ}
  • 1.24\displaystyle nm
  • 12.4 \displaystyle nm
A surface has work function 3.3 eV . Which of the following will cause emission?
  • 100 W incandascent lamp
  • 40 W flouroscent lamp
  • 20 W sodium lamp
  • 20 W Hg lamp
Find the wavelength of 10 MeV \ \alpha-particles
  • 3 A^{\circ}
  • 3 pm
  • 3 fm
  • 30 fm
In the following diagram if \displaystyle V_{2}>V_{1}then
153456.jpg
  • \displaystyle \lambda _{1}=\sqrt{\lambda _{2}}
  • \displaystyle \lambda _{1}<\lambda _{2}
  • \displaystyle \lambda _{1}=\lambda _{2}
  • \displaystyle \lambda _{1}>\lambda _{2}
The work function of a metal is 2.5 eV. When photon of some proper energy is made incident on it, then an electron of 1.5 eV is emitted. The energy of photon will be 
  • 4 eV
  • 1 eV
  • 1.5 eV
  • 2.5 eV
The number of photons of wavelength 13.2 A^{0} in 6 J of energy is:
(h=6.6\times10^{-34} Js)
  • 2\times10^{12}
  • 4\times10^{16}
  • 6\times10^{20}
  • 4\times10^{24}
The relation between energy E and momentum p of a photon is
  • E = pc
  • E=\dfrac { p }{ c }
  • p = Ec
  • E=\dfrac { { p }^{ 2 } }{ c }
The effective mass of photon of wavelength 40 \overset { \circ  }{ A } will be:
  • 55.2\times { 10 }^{ -35 }kg
  • 55.2\times { 10 }^{ -33 }gm
  • 55.2\times { 10 }^{ -17 }kg
  • 55.2\times { 10 }^{ -38 }kg
Two electrons are moving with the same velocity, one electron enters a region of uniform electric field while the other enters a region of uniform magnetic field. Then, after sometime, if the de-Broglie wavelength of two are \lambda_{1} and \lambda_{2} respectively, then
  • \lambda_{1} = \lambda_{2}
  • \lambda_{1} > \lambda_{2}
  • \lambda_{1} < \lambda_{2}
  • \lambda_{1}>\lambda_{2} or \lambda_{1}< \lambda_{2}

Find the minimum wavelength of X-ray produced if 10 kV potential difference is applied across the anode and cathode of the tube.

  • 12.4 A^{\circ}
  • 12.4 nm
  • 1.24 nm
  • 1.24 A^{\circ}
The correct curve between the energy of photon (E) and its wave length\ \lambda is
A radio transmitter is working at frequency 880 kHz and power 10kW. The number of photons emitted per second will be 
  • \displaystyle 1327\times 10^{34}
  • \displaystyle 0.075\times 10^{-34}
  • \displaystyle 1.71\times 10^{31}
  • \displaystyle 13.27\times 10^{34}
The momentum of photon of frequency { 10 }^{ 14 }Hz will be
  • 2.2\times { 10 }^{ -26 }Kg \ m/sec
  • 2.21\times { 10 }^{ -28 }Kg \ m/sec
  • { 10 }^{ -28 }Kg \ m/sec
  • 0.21\times { 10 }^{ -2 }Kg \ m/sec
Protons are accelerated from rest by a potential difference 4 kV and strike a metal target. If a proton produces one photon on impact of minimum wavelength \lambda_1 and similarly an electron accelerated to 4 kV strikes the target and produces a minimum wavelength \lambda_2 then
  • \lambda_1 = \lambda_2
  • \lambda_1 > \lambda_2
  • \lambda_1 < \lambda_2
  • no such relation can be established
Neglecting variation of mass with energy the wavelength associated with an electron having a kinetic energy E is proportional to 
  • E^{1/2}
  • E
  • E^{-1/2}
  • E^{-2}
When an electron moving at a high speed strikes a metal surface, which of the following are possible?
  • The entire energy of the electron may be converted into an X-ray photon
  • Any fraction of the energy of the electron may be converted into an X-ray photon.
  • The entire energy of the electron may get converted to heat.
  • The electron may undergo elastic collision with the metal surface.
An electron makes transition from n=4 to n=1 state in a hydrogen atom. The maximum possible number of photons emitted will be :
  • 1
  • 2
  • 3
  • 6
On increasing the applied potential difference in X-ray tube
  • The intensity of emitted radiation increases.
  • The minimum wavelength of emitted radiation increases.
  • The intensity of emitted radiation remains unchanged.
  • The minimum wavelength of emitted radiation decreases.
0:0:1


Answered Not Answered Not Visited Correct : 0 Incorrect : 0

Practice Class 12 Medical Physics Quiz Questions and Answers