Q.1
The lowest frequency of light that will cause the emission of photoelectrons from the surface of a metal ( for which work function is 1.65 eV) will be [ JIPMER 2002]
  • a)4 × 1010 Hz
  • b) 4 × 1011Hz
  • c)4 × 1014 Hz
  • d)4 × 10⁻¹⁰ Hz
Q.2
When radiation of wavelength λ is incident on a metallic surface, the stopping potential is 4.8 V. If the same surface is illuminated with radiation of double wavelength, then the stopping potential becomes 1.6V. Then threshold wavelength for the surface is [ EAMCET 2003]
  • a) 3λ
  • b) 4λ
  • c)6λ
  • d)8λ
Q.3
The energy of photon is equal to the K.E. of a proton. The energy of the photon is E. Let λ1 be the de-Broglie wavelength of the proton and λ2 be the wavelneth of photon. the ratio of λ;1 / λ2 is proprortioanl to [ IIT 2004]
  • a) Eo
  • b) E1/2
  • c)E-1
  • d)E-2
Q.4
If K1 and K2 are maximum kinetic energies of photoelectrons emitted when lights of wavelength λ1 and λ2 respectively incident on a metallic surface. If λ1=3λ2 the [ EAMCET 2004]
  • c) 3K1=K2
  • d) K1=3K2/3
  • a) K₁ ≥ K₂/3
  • b) K₁ < K₂/3
Q.5
If E and p are the respective energy and momentum of photon, then on reducing the wavelength of the photon
  • a)both p and E will decrease
  • b) both p and E will increase
  • c)p will increase but E will decrease
  • d)p will decrease but E will increase
Q.6
the momentum of photon of energy 1MeV will approximately be
  • a) 10-22 kg-m/s
  • b) 5 × 10⁻²² kg-m/s
  • c)3 × 106 kg-m/s
  • d)0
Q.7
The study of diffraction of electrons from a target, gives the wavelength associated as 0.65 Å. the energy of the electrons will be
  • a) 40 eV
  • b) 100 eV
  • c)356 eV
  • d)1000 eV
Q.8
the energies of an photon of a mass m and electron are same. velocity of electron is v, the ratio of wave lengths associated with them will be
  • a)
    ch-9_qn-204choice_img_no1.png
  • b)
    ch-9_qn-204choice_img_no2.png
  • c)
    ch-9_qn-204choice_img_no3.png
  • d)
    ch-9_qn-204choice_img_no4.png
Q.9
Two particles of same mass m1 and m2 respectively are identically charged and are accelerated by same potential. If de-Broglie wavelength associated with them are λ1 and λ2 then
  • a) λ1 / λ2=m₂ / m₁
  • b) λ1 / λ2=√( m₂ / m₁)
  • c)λ1 / λ2=m₁ / m₂
  • d)λ1 / λ2=√( m₁ / m₂)
Q.10
An electron is 2000 times lighter than a proton. An electron and a proton are moving with such a velocity that de-Broglie wave associated with them is 1 Å
  • a) 1:2000
  • b) 2000 : 1
  • c)1:1
  • d)1:(4.0106)
Q.11
A double slit interference experiment is performed by a beam of electrons of energy 100eV and fring spacing is observed to be β. Now if the electrons energy is increased to 10keV, then the fring spacing
  • a) remains the same
  • b) becomes 10β
  • c)becomes 100β
  • d)becomes β/10
Q.12
An electron beam of energy 10keV is passed through a slit of width 1 mm. the observed phenomenon will be
  • a) interference
  • b) diffraction
  • c) rectilinear propogation
  • d) polarisation
Q.13
The wave-nature of electron was verified by
  • a)photoelectric effect
  • b) Compton effect
  • c)the incidence of electron on metallic surface
  • d)diffraction of electron by crystal
Q.14
In Davisson -Germaer experiment, electrons are produced by
  • a) the photo-electric effect
  • b) the thermionic emission
  • c)the electric effect
  • d)Schottky effect
Q.15
Wrong statement in connection with Devisson-Germer experiment is
  • a) The inter-atomic distance in Nickel crystal is of the order of the de-Broglie wavelength
  • b) Electrons of constant energy are obtained by the electron gun
  • c)Nickel crystal acts as a three dimensional diffracting grating
  • d)Davision-Germer experiment is an interference experiment
Q.16
In Devision-Germer experiment maximum intensity is observed at
  • a) 50° and 54 volts
  • b) 54° and 50 volts
  • c) 50° and 50 volt
  • d) 65° and 50 volt
Q.17
the interatomic distance between atom in a crystal is 2.8 Å. then if such a crystal is used in Davisson-Germer experiment, the maximum order of diffraction that can be observed for a beam of electrons accelerated by 100V shall be
  • a)n=1
  • b) n=2
  • c)n=10
  • d)n=∞
Q.18
The angle between the incident and the diffracted electron in the Davisson-Germer experiment is called as
  • a) angle of incidence
  • b) angle of diffraction
  • c)angle of scattering
  • d)none of above
Q.19
The distance between two consecutive atoms of the crystal lattice is 1.227 Å . the maximum order of diffraction of electrons accelerated through 104 volts will be
  • a) 10
  • b) 1/10
  • c)100
  • d)1/100
Q.20
If the spacing between lattice plane of a crystal be d and wavelength of electron be λ, then for observing the diffraction of electron from the crystal, it is essential that
  • a) 2d ≥ λ
  • b) λ ≥ 2d
  • c) 4d ≥ λ
  • d) λ ≥ d
Q.21
A proton when accelerated through a potential difference of V volt has a wavelength λ associated with it . An alpha particle , in order to have same λ, must be accelerated through a potential difference of
  • a)V volt
  • b) 4V volt
  • c)2V volt
  • d)V/8 volt
Q.22
The potential in electron microscope is increased from 3kV to 9kV, if the initial resolving power of microscope is R then, its new resolving power will be
  • a) R
  • b) 2R
  • c)√3 R
  • d)√5 R
Q.23
Silver has workfunction of 4.7eV. When ultraviolet light of wavelength 100nm is incident upon it, a potential of 7.7 volt is required to stop the photoelectrons from reaching the collector plate. the potential required to stop photo electrons when light of wavelength 200nm is incident upon silver is
  • a) 1.5V
  • b) 1.85 V
  • c)1.95 V
  • d)2.37 V
Q.24
When a light source is placed at a distance of 1m from the emitter, it emits electrons of energy 4eV. IF the distance is changed to 0.5m, then
  • a) the number of electrons emitted will be same but their energy will become double
  • b) the number of electrons emitter will be same but there energy will become four times
  • c)it will emit twice the number of electrons of same energy
  • d)it will emit four times the number of electrons in earlier case with same energy
Q.25
Light of wavelength 5000Å and intensity 3.98 mW/cm2 is incident on a light sensitive surface. If 1% photons of incident light causes emission of the photoelectrons, then how many electrons will be emitted from 1m2 area of the surface
  • a) 1016
  • b) 1018
  • c) 1020
  • d) 1022
Q.26
The kinetic energy of the photoelectrons is E. When the incident wavelength is λ/The Kinetic energy become 2E when the incident wavelength is λ/The work function of the metal is
  • a)hc/λ
  • b) 2hc/λ
  • c)3hc/λ
  • d)hc/3λ
Q.27
The electric field associated with a light wave is E=Eo sin [1.57 × 107( x-ct)] where x is in metrre and t is in second. If this light is used to produce photoelectric emission from the surface of metal of workfunction 1.9eV, then the stopping potential will be
  • a) 1.2V
  • b) 1.5 V
  • c)1.75 V
  • d)1.9 V
Q.28
In the diagram, graphs are drawn between stopping potential Vo and frequency ν for the elements K and Ca. According to this to diagram
ch-9_que_no-227_img_no1.png
  • a)workfunction of K and Ca are equal
  • b) workfunction of K is greater than that of Ca
  • c)the workfunction of K is less than that of Ca
  • d)no information can be obtained about the workfunction
Q.29
Electrons of 0.5 eV energy are emitted from a metal surface when photons of wavelength 3000Å are incident. the energy of electrons, when photons of 2000Å are incident ill be
  • a)equal to 0.5 eV
  • b) higher than 0.5eV
  • c)less than 0.5eV
  • d)none of the above
Q.30
Lights of two different frequencies, whose photons have energies 1 and 2.5 eV respectively, successively illuminate a metal whose workfunction is 0.5eV. The ratio of the maximum speed of the emitted electron will be
  • a) 1 : 5
  • b) 1:4
  • c)1:2
  • d)1:1
0 h : 0 m : 1 s