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

The kinetic energy of electron and proton is 1032 J. Then the relation between their de-Broglie wavelength is 
  • λp<λe
  • λp>λe
  • λp=λe
  • λp=2λe
AN important spectral emission line has a wavelength of 21 cm. The corresponding photon energy is
  • 5.9×104eV
  • 5.9×106eV
  • 5.9×108eV
  • 11.8×106eV
Which of the following is true for photon
  • E=hcλ
  • E=12mu2
  • p=E2v
  • E=12mc2
The de-Broglie wavelength is proportional to 
  • λ1v
  • λ1m
  • λ1p
  • λp
The spectrum of radiation 1.0×1014Hz is the infrared region. The energy of one photon of this in joules will be
  • 6.62×1048
  • 6.62×1020
  • 6.623×1028
  • 3×6.62×1028
A laser is a coherent source because it contains
  • Many wavelengths
  • Unconditinated wave of a particular wavelength
  • Coordinated wave of many wavelengths
  • Coordinated wave of particular wavelengths
The minimum wavelength of photons is 5000oA, its energy will be 
  • 2.5 eV
  • 50 eV
  • 5.48 eV
  • 7.48 eV
If the energy of a photon correspoiding to a wavelength of 6000oA is 3.32×1019J, the photon energy for a wavelength of 4000oA will be
  • 1.4 eV
  • 4.9 eV
  • 3.1 eV
  • 1.6 eV
de-Broglie wavelength of a body of mass m and kinetic energy E is given by 
  • λ=hmE
  • λ=2mEh
  • λ=h2mE
  • λ=h2mE
A proton and an α particle are acclerated through a potential difference of 100 V. The ratio of the wavelength associated with the proton to that associated with an α- particle is 
  • 2:1
  • 2:1
  • 22:1
  • 122:1
The log-log graph between the energy E of an electron and its de-Broglie wavelength λ will be
For moving ball of cricket, the correct statement about de-Broglie wavelength is 
  • It is not applicable for such big particle
  • h2mE
  • h2mE
  • h2mE
An electron is moving through a field. It is moving (i) opposite an electric field (ii) perpendicular to a magnetic field as shown. For each situation the de-Broglie wave length of electron
1818527_ca2edb846723479eb6041b12e5edc099.png
  • Increasing, Increasing
  • Increasing,decreasing
  • Decreasing, same
  • same,same
Find out the de-Broglie wavelength related to an electron of kinetic energy 10 eV:
  • 10˚A
  • 1227˚A
  • 0.10˚A
  • 3.9˚A
The output from a LASER is monochromatic. It means that it is
  • Directional
  • Polarised
  • Narrow beam
  • Single frequency
Given below are two statements:
Statement I: Two photons having equal linear momenta have equal wavelengths.
Statement- II: If the wavelength of photon is decreased, then the momentum and energy of a photon will also decrease. 
In the light of the above statements, choose the correct answer from the options given below. 
  • Both Statement I and Statement II are true.
  • Statement I is false but Statement II is true
  • Both Statement I and Statement II are false
  • Statement I is true but Statement II is false
The wavelength of the de-Broglie wave associated with a thermal neutron of mass m at absolute temperature T is given by: 
(k is the Boltzmann constant)
  • hmkT
  • h2mkT
  • h3mkT
  • h2mkT
What should be the approximate K.E. of an electron so that its de -Broglie wavelength is equal to the wavelength of x -ray of maximum energy produced in an x -ray tube operating at 24,800 V? (h=6.6/×1034Jsec, mass of electron m=9.1×1031kg) (give answer in 102eV).
  • 3
  • 4
  • 6
  • 9
Photoelectrons emitted from a photo sensitive metal of work function 1eV describe a circle of radius 0.1 cm in a magnetic field of induction 103 Tesla. The energy of the incident photons is (mass of electron =9×1031kg)
  • 1.17eV
  • 2.9eV
  • 0.9eV
  • 0.81eV
A proton is fired from very far away towards a nucleus with charge Q = 120 e, where e is the electronic charge. It makes a closest approach of 10 fm to the nucleus. The de Broglie wavelength (in units of fm) of the proton at its start is :

 (take the proton mass, mp=(5/3)×1027kg and

h/e=4.2×1015J.s/C;14πϵ0=9×109m/F;1fm=1015m)
  • 7 fm
  • 8 fm
  • 9 fm
  • 10 fm
The light of radiation 300nm falls on a photocell operating in the saturation mode. The spectral sensitivity is 4.8mA/W. The yield of photo electrons (i.e. number of electrons produced per photon) is
  • 0.04
  • 0.02
  • 0.03
  • 0.2
The de-Broglie wavelength of a neutron at 9270C isλ. Its wavelength at 270C is:
  • λ2
  • λ
  • 2λ
  • 4λ
Choose the correct statements from the following about photoelectric emission
  • For given emitter illuminated by light of a given frequency, the number of photoelectrons emitted per second is proportional to the intensity of incident light
  • For every emitter there is a definite threshold frequency below which no photo electrons are emitted, no matter what the intensity of light is
  • Above the threshold frequency, the maximum kinetic energy of photo electrons is proportional to the frequency of incident light
  • The saturation value of the photoelectric current is independent of the intensity of incident light
When photons of energy 4.25eV strike the surface of a metal A, the ejected photoelectrons have maximum kinetic energy of KA eV and de Broglie wavelength λA. The maximum kinetic energy of photo electrons liberated from another metal B by photons of energy 4.70eV is KB=(KA1.5)eV. If the de Broglie wavelength of these photoelectrons is λB=2λA then
  • the work function of A is 2.25 eV
  • the work function of B is 4.20 eV
  • KA=2.00 eV
  • KB=2.75 eV
Select correct alternative :
Statement -1 : An electric dipole can not produce zero electric field at a point which is situated at finite distance from the dipole.
Statement -2 : Mass of a moving photon is proportional to λ1 .
Statement -3 : Equation of continuity for fluid is based on conservation of volume.
  • FFF
  • TTF
  • TFF
  • TTT
The number of photons emitted per second by a 40W lamp, if 15% of the energy appears as the radiation of wavelength 540 nm is
  • 1.63×1019
  • 1.5×1010
  • 2.2×1010
  • 1.63×1018
A photosensitive metallic surface has work function, h 0. If photons of energy 2h 0 fall on this surface, the electrons come out with a maximum velocity of 4 106 m/s. When the photon energy is increased to 5h0, then maximum velocity of photo electrons will be
  • 2 107 m/s
  • 2 106 m/s
  • 8 105 m/s
  • 8 106 m/s
A point source of light of power P and wavelength λ is emitting light in all directions. The number of photons present in a spherical region of radius r to radius r+x with centre at the source is:
  • Pλ4πr2hc
  • Pλxhc2
  • Pλx4πr2hc
  • None of these
A charge particle q0 of mass m0 is projected along the y-axis at t=0 from origin with a velocity V0. If a uniform electric field E0 also exists along the x-axis, then the time at which de Broglie wavelength of the particle becomes half of the initial value is :
  • m0v0q0E0
  • 2m0v0q0E0
  • 3m0v0q0E0
  • 3m0v0q0E0
A particle of mass m  is projected from ground with velocity u  making an angle θ  with the vertical. The de-Broglie wavelength of the particle at the highest point is 
  • hmusinθ
  • hmucosθ
  • hmu
If the shortest wavelength of the continuous X-ray spectrum coming out of a Coolidge tube is 0.01nm, then the de Broglie wavelength of the electron reaching the target metal in the Coolidge tube is approximately
(hc=12400eVA,h=6.63×1034 in  MKS, mass  of  electron=9.1×1031kg)
  • 0.35
  • 0.035
  • 35
  • 1350
A small 50 kg vehicle is designed to be moved in free space by a lamp which emits 100 watts of red light of λ=6630Ao. What is its acceleration?
  • 6.66×109 m/sec2
  • 3×109 m/sec2
  • 2.22×109 m/sec2
  • 4.44 m/sec2
A photon of frequency v has an energy
  • hv
  • vh
  • v
  • hv
If a hydrogen atom at rest, emits a photon of wavelength λ, the recoil speed of the atom of mass m is given by 
  • hmλ
  • mhλ
  • mhλ
  • none of these
Photoelectric effect is described as the ejection of electrons from the surface of metal when
  • It is heated to high temperature
  • Light of suitable wavelength falls on it
  • Electrons of a suitable velocity impinge on it
  • It is placed in a strong magnetic field
Photoelectric effect can be explained only by assuming that
  • Light is a form of transverse waves
  • Light is a form of longitudinal waves
  • Light can be polarised
  • Light consists of quanta
A light of wavelength λ is incident on a metal sheet of work function ϕ=2eV. The  wavelength λ varies with time as λ=3000+40t,whereλ is in and t is in second. The power incident on metal sheet is constant at 100 W. This signal is switched on and off for time intervals of 2 minutes and 1 minute respectively. Each time the signal is switched on, the λ start from an initial value of 3000. The metal plate is grounded and electron clouding is negligible. The efficiency of photoemission is 1%(hc=12400eV)The time after which photo-emission will stop is 
  • 79 s
  • 80 s
  • 81 s
  • 78 s
A proton and an electron are accelerated by the same potential difference. Let λe and λp denote the de Broglie wavelengths of the electron and the proton respectively.
  • λe=λp
  • λe<λp
  • λe>λp
  • λe and λp depend on the accelerating potential difference.
If the shortest wavelength of the continuous X-ray spectrum coming out of a Coolidge tube is 0.1˚A, then the de Broglie wavelength of the electron reaching the target metal in the Coolidge tube is approximately 
(hc=12400eV˚A, h=6.63×1034 in MKS, mass of electron =9.1×1031kg)
  • 0.35˚A
  • 0.035˚A
  • 35˚A
  • 3.5˚A
If we assume that penetrating power of any radiation/particle is inversely proportional to the De-broglie wavelength of the particle, then
  • A proton and an αparticle after getting accelerated through same potential difference will have equal penetrating power.
  • Penetrating power of αparticle will be greater than that of proton which have been accelerated by same potential difference.
  • Proton's penetrating power will be less than penetrating power of an electron which has been accelerated by the same potential difference.
  • Penetrating powers can not be compared as all these are particles having no wavelength or wave nature.
A photon of frequency v has a momentum associated with it. If c is the velocity of light, then momentum is
  • hvc2
  • hvc
  • vc
  • hvc
A photon is an
  • Quantum of light energy
  • Quantum of matter
  • Positively charged particle
  • instrument for measuring light intensity
Two particles of masses m and 2m have equal kinetic energies. Their de Broglie wavelengths are in the ratio of :
  • 1:1
  • 1:2
  • 1:2
  • 2:1
Will the radiation from a 50 kW, 100 MHz FM station expose the film?
  • No
  • Yes
  • Cannot Say
  • Incomplete data
The idea of quantum nature of light has emerged in an attempt to explain
  • The thermal radiation of a black body
  • The interference of light
  • Radioactivity
  • Thermionic emission
Find the frequency of photon.
  • 2.71 × 1014Hz
  • 2.01 × 1014Hz
  • 2.5 × 1014Hz
  • 20.1 × 1014Hz
Mass of the photon at rest is
  • 1.67×1035kg
  • One a.m.u
  • 9×1031kg
  • Zero
de Broglie relation is true  for
  • All particles
  • Charged particles only
  • Negatively charged particles only
  • Massless particles like photons only
A ray of energy 14.2 Me V is emitted from a 60Co nucleus. The recoil energy of the co-nucleus is nearly 
  • 3×1010J
  • 3×1015J
  • 3×1014J
  • 3×1013J
A  proton and an electron are accelerated by the same potential difference. Let λc and λp denote the de Broglie wavelengths of the electron and the proton respectively.
  • λc=λp
  • λc<λp
  • λc>λp
  • The relation between λc and λp depends on the accelerating potential difference.
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Practice Class 12 Medical Physics Quiz Questions and Answers