JEE Main & Advanced Physics Photo Electric Effect, X- Rays & Matter Waves Question Bank

done Photon and Photoelectric Effect Total Questions - 155

• question_answer1)
  The momentum of a photon is\[3.3\times {{10}^{-29}}kg-\]m/sec. Its frequency will be  [CPMT 1980; MP PET 1992; DPMT                    1999]
  A)
             \[3\times {{10}^{3}}Hz\]  done clear
  B)
             \[6\times {{10}^{3}}Hz\] done clear
  C)
             \[7.5\times {{10}^{12}}Hz\]    done clear
  D)
             \[1.5\times {{10}^{13}}Hz\] done clear
  View Solution play_arrow

• question_answer2)
  The energy of a photon of wavelength \[\lambda \]is given by   [CPMT 1974; CBSE PMT 1992; DCE 1998; BHU 2000; DPMT 2001]
  A)
             \[h\lambda \]                       done clear
  B)
             \[ch\lambda \] done clear
  C)
             \[\lambda /hc\]                   done clear
  D)
             \[hc/\lambda \] done clear
  View Solution play_arrow

• question_answer3)
  The momentum of a photon is\[2\times {{10}^{-16}}\]gm-cm/sec. Its energy is                                 [CPMT 1974]
  A)
             \[0.61\times {{10}^{-26}}erg\]                                          done clear
  B)
             \[2.0\times {{10}^{-26}}erg\] done clear
  C)
             \[6\times {{10}^{-6}}erg\]       done clear
  D)
             \[6\times {{10}^{-8}}erg\] done clear
  View Solution play_arrow

• question_answer4)
  The rest mass of the photon is         [MP PET 1994; CPMT 1996; RPMT 1999; JIPMER 2002]
  A)
             0 done clear
  B)
             \[\infty \] done clear
  C)
             Between 0 and \[\infty \] done clear
  D)
             Equal to that of an electron done clear
  View Solution play_arrow

• question_answer5)
  The momentum of the photon of wavelength 5000Å  will be [CPMT 1987]
  A)
             \[1.3\times {{10}^{-27}}kg\text{-}\]m/sec                   done clear
  B)
             \[1.3\times {{10}^{-28}}kg\text{-}\]m/sec done clear
  C)
             \[4\times {{10}^{29}}kg\text{-}\]m/sec                        done clear
  D)
             \[4\times {{10}^{-18}}kg\text{-}\]m/sec done clear
  View Solution play_arrow

• question_answer6)
  The momentum of a photon of energy \[h\nu \]will be  [DCE 2000]
  A)
             \[h\nu \]                                 done clear
  B)
             \[h\nu /c\] done clear
  C)
             \[h\nu c\]                               done clear
  D)
             \[h/\nu \] done clear
  View Solution play_arrow

• question_answer7)
  A photon in motion has a mass        [MP PMT 1992]
  A)
             \[c/h\nu \]                             done clear
  B)
             \[h/\nu \] done clear
  C)
             \[h\nu \]                                 done clear
  D)
             \[h\nu /{{c}^{2}}\] done clear
  View Solution play_arrow

• question_answer8)
  If the momentum of a photon is p, then its frequency is [MP PET 1989]
  A)
             \[\frac{ph}{c}\]                    done clear
  B)
             \[\frac{pc}{h}\] done clear
  C)
             \[\frac{mh}{c}\]                   done clear
  D)
             \[\frac{mc}{h}\] Where m is the rest mass of the photon done clear
  View Solution play_arrow

• question_answer9)
  An AIR station is broadcasting the waves of wavelength 300 metres. If the radiating power of the transmitter is 10 kW, then the number of photons radiated per second is [MP PET 1989; RPMT 2000]
  A)
             \[1.5\times {{10}^{29}}\] done clear
  B)
             \[1.5\times {{10}^{31}}\] done clear
  C)
             \[1.5\times {{10}^{33}}\] done clear
  D)
             \[1.5\times {{10}^{35}}\] done clear
  View Solution play_arrow

• question_answer10)
  The energy of a photon is \[E=hv\] and the momentum of  photon \[p=\frac{h}{\lambda }\], then the velocity of photon will be [CPMT 1991]
  A)
             E/p done clear
  B)
             Ep done clear
  C)
             \[{{\left( \frac{E}{p} \right)}^{2}}\]                                 done clear
  D)
             \[3\times {{10}^{8}}m/s\] done clear
  View Solution play_arrow

• question_answer11)
  The approximate wavelength of  a photon of energy 2.48 eV is                                                  [MP PMT 1987]
  A)
             500 Å                                        done clear
  B)
             5000 Å done clear
  C)
             2000 Å                                      done clear
  D)
             1000 Å done clear
  View Solution play_arrow

• question_answer12)
  An important spectral emission line has a wavelength of 21 cm. The corresponding photon energy is [MP PMT 1993]
  A)
             \[5.9\times {{10}^{-4}}eV\]    done clear
  B)
             \[5.9\times {{10}^{-6}}eV\] done clear
  C)
             \[5.9\times {{10}^{-8}}eV\]    done clear
  D)
             \[11.8\times {{10}^{-6}}eV\] \[(h=6.62\times {{10}^{-34}}Js;\ \ c=3\times {{10}^{8}}m/s)\] done clear
  View Solution play_arrow

• question_answer13)
  The momentum of a photon in an X-ray beam of \[{{10}^{-10}}\]metre wavelength is                                    [MP PET 1996]
  A)
             \[1.5\times {{10}^{-23}}kg-\]m/sec                                 done clear
  B)
             \[6.6\times {{10}^{-24}}kg-m/\sec \] m/sec done clear
  C)
             \[6.6\times {{10}^{-44}}kg-m/\sec \]m/sec                 done clear
  D)
             \[2.2\times {{10}^{-52}}kg-m/\sec \] m/sec done clear
  View Solution play_arrow

• question_answer14)
  The energy of a photon of light with wavelength 5000 Å is approximately 2.5 eV. This way the energy of an X-ray photon with wavelength 1Å would be              [MP PET 1997]
  A)
             2.5/5000 eV                           done clear
  B)
             \[2.5/{{(5000)}^{2}}eV\] done clear
  C)
             \[2.5\times 5000\ eV\]     done clear
  D)
             \[2.5\times {{(5000)}^{2}}eV\] done clear
  View Solution play_arrow

• question_answer15)
  Energy of a quanta of frequency \[{{10}^{15}}\]Hz and \[h=6.6\times {{10}^{-34}}J\text{-}\sec \] will be                                   [RPMT 1997]
  A)
             \[6.6\times {{10}^{-19}}J\]      done clear
  B)
             \[6.6\times {{10}^{-12}}J\] done clear
  C)
             \[6.6\times {{10}^{-49}}J\]      done clear
  D)
             \[6.6\times {{10}^{-41}}J\] done clear
  View Solution play_arrow

• question_answer16)
  Momentum of a photon of wavelength l is [CBSE PMT 1993; JIPMER 2001, 02]
  A)
             \[\frac{h}{\lambda }\]       done clear
  B)
             Zero done clear
  C)
             \[\frac{h\lambda }{{{c}^{2}}}\]                                         done clear
  D)
             \[\frac{h\lambda }{c}\] done clear
  View Solution play_arrow

• question_answer17)
  Wavelength of a 1 keV photon is \[1.24\times {{10}^{-9}}m\]. What is the frequency of 1 MeV photon [CBSE PMT 1993; MP PET 2005]
  A)
             \[1.24\times {{10}^{15}}Hz\]  done clear
  B)
             \[2.4\times {{10}^{20}}Hz\] done clear
  C)
             \[1.24\times {{10}^{18}}Hz\]  done clear
  D)
             \[2.4\times {{10}^{23}}Hz\] done clear
  View Solution play_arrow

• question_answer18)
  What is the momentum of a photon having frequency \[1.5\times {{10}^{13}}Hz\]                                           [BHU 1997]
  A)
             \[3.3\times {{10}^{-29}}kg\ m/s\]                                    done clear
  B)
             \[3.3\times {{10}^{-34}}kg\ m/s\] done clear
  C)
             \[6.6\times {{10}^{-34}}kg\ m/s\]                                    done clear
  D)
             \[6.6\times {{10}^{-30}}kg\ m/s\] done clear
  View Solution play_arrow

• question_answer19)
  The energy of a photon of light of wavelength 450 nm is [BHU 1997; JIPMER 2000]
  A)
             \[4.4\times {{10}^{-19}}J\]      done clear
  B)
             \[2.5\times {{10}^{-19}}J\] done clear
  C)
             \[1.25\times {{10}^{-17}}J\]   done clear
  D)
             \[2.5\times {{10}^{-17}}J\] done clear
  View Solution play_arrow

• question_answer20)
  Frequency of photon having energy 66 eV is [CPMT PMT 1997]
  A)
             \[8\times {{10}^{-15}}Hz\]      done clear
  B)
             \[12\times {{10}^{-15}}Hz\] done clear
  C)
             \[16\times {{10}^{15}}Hz\]     done clear
  D)
             None of these done clear
  View Solution play_arrow

• question_answer21)
  Which of the following statement is not correct  [AFMC 1999]
  A)
             Photographic plates are sensitive to infrared rays done clear
  B)
             Photographic plates are sensitive to ultraviolet rays done clear
  C)
             Infra-red rays are invisible but can cast shadows like visible light done clear
  D)
             Infrared photons have more energy than photons of visible light done clear
  View Solution play_arrow

• question_answer22)
  If we express the energy of a photon in KeV and the wavelength in angstroms, then energy of a photon can be calculated from the relation                           [AMU (Engg.) 1999]
  A)
             \[E=12.4\,h\nu \]                done clear
  B)
             \[E=12.4\,h/\lambda \] done clear
  C)
             \[E=12.4\,/\lambda \]       done clear
  D)
             \[E=h\nu \] done clear
  View Solution play_arrow

• question_answer23)
  The frequency of a photon, having energy 100 \[eV\] is\[(h=6.6\,{{10}^{-34}}\,J\text{-}sec)\]                               [AFMC 2000]
  A)
             \[2.42\times {{10}^{26}}Hz\]  done clear
  B)
             \[2.42\times {{10}^{16}}Hz\] done clear
  C)
             \[2.42\times {{10}^{12}}Hz\]  done clear
  D)
             \[2.42\times {{10}^{9}}Hz\] done clear
  View Solution play_arrow

• question_answer24)
  A photon of wavelength 4400 Å is passing through vacuum. The effective mass and momentum of the photon are respectively                                          [AMU 2000]
  A)
             \[5\times {{10}^{-36}}kg,\,\,1.5\times {{10}^{-27}}\,kg\text{-}m/s\] done clear
  B)
             \[5\times {{10}^{-35}}kg,\,\,1.5\times {{10}^{-26}}\,kg\text{-}m/s\] done clear
  C)
             Zero, \[1.5\times {{10}^{-26}}\,kg\text{-}m/s\] done clear
  D)
             \[5\times {{10}^{-36}}kg,\,1.67\times {{10}^{-43}}kg\text{-}m/s\] done clear
  View Solution play_arrow

• question_answer25)
  Which of the following is true for photon             [RPET 2001]
  A)
              \[E=\frac{hc}{\lambda }\]      done clear
  B)
             \[E=\frac{1}{2}m{{u}^{2}}\] done clear
  C)
             \[p=\frac{E}{2v}\]               done clear
  D)
             \[E=\frac{1}{2}m{{c}^{2}}\] done clear
  View Solution play_arrow

• question_answer26)
  Which of the following is incorrect statement regarding photon [MH CET (Med.) 2001]
  A)
             Photon exerts no pressure done clear
  B)
             Photon energy is \[hv\] done clear
  C)
             Photon rest mass is zero done clear
  D)
             None of these done clear
  View Solution play_arrow

• question_answer27)
  If a photon has velocity c and frequency n, then which of following represents its wavelength [AIEEE 2002]
  A)
             \[\frac{hc}{E}\]                    done clear
  B)
             \[\frac{h\nu }{c}\] done clear
  C)
             \[\frac{h\nu }{{{c}^{2}}}\]       done clear
  D)
             \[h\nu \] done clear
  View Solution play_arrow

• question_answer28)
  The mass of a photo electron is                                                                 [MP PMT 2002]
  A)
             \[9.1\times {{10}^{-27}}\,kg\]                                           done clear
  B)
             \[9.1\times {{10}^{-29}}\,kg\] done clear
  C)
             \[9.1\times {{10}^{-31}}\,kg\]                                           done clear
  D)
             \[9.1\times {{10}^{-34}}\,kg\] done clear
  View Solution play_arrow

• question_answer29)
  Energy of photon whose frequency is \[{{10}^{12}}MHz,\] will be  [MH CET 2002]
  A)
              \[4.14\times {{10}^{3}}keV\]                                            done clear
  B)
             \[4.14\times {{10}^{2}}eV\] done clear
  C)
             \[4.14\times {{10}^{3}}MeV\]                                           done clear
  D)
             \[4.14\times {{10}^{3}}eV\] done clear
  View Solution play_arrow

• question_answer30)
  There are \[{{n}_{1}}\] photons of frequency \[{{\gamma }_{1}}\] in a beam of light. In an equally energetic beam, there are \[{{n}_{2}}\] photons of frequency \[{{\gamma }_{2}}\]. Then the correct relation is    [KCET 2003]
  A)
              \[\frac{{{n}_{1}}}{{{n}_{2}}}=1\]                                      done clear
  B)
             \[\frac{{{n}_{1}}}{{{n}_{2}}}=\frac{{{\gamma }_{1}}}{{{\gamma }_{2}}}\] done clear
  C)
             \[\frac{{{n}_{1}}}{{{n}_{2}}}=\frac{{{\gamma }_{2}}}{{{\gamma }_{1}}}\]     done clear
  D)
             \[\frac{{{n}_{1}}}{{{n}_{2}}}=\frac{\gamma _{1}^{2}}{\gamma _{2}^{2}}\] done clear
  View Solution play_arrow

• question_answer31)
  Einstein's photoelectric equation states that                                                                                          \[{{E}_{k}}=h\nu -\varphi\] . In this equation                                                                                              \[3\times {{10}^{23}}\]  refers to [CPMT 1982; MP PMT 1997]
  A)
             Kinetic energy of all the emitted electrons done clear
  B)
             Mean kinetic energy of the emitted electrons done clear
  C)
             Maximum kinetic energy of the emitted electrons done clear
  D)
             Minimum kinetic energy of the emitted electrons done clear
  View Solution play_arrow

• question_answer32)
  Kinetic energy with which the electrons are emitted from the metal surface due to photoelectric effect is [CPMT 1973]
  A)
             Independent of the intensity of illumination done clear
  B)
             Independent of the frequency of light done clear
  C)
             Inversely proportional to the intensity of illumination done clear
  D)
             Directly proportional to the intensity of illumination done clear
  View Solution play_arrow

• question_answer33)
  The threshold wavelength for photoelectric emission from a material is 5200 Å.  Photo-electrons will be emitted when this material is illuminated with monochromatic radiation from a               [IIT JEE 1982; MP PMT 1992; MP PET 1999; UPSEAT 2001; KCET 2004; J & K CET 2004; BHU 2004]
  A)
             50 watt infrared lamp done clear
  B)
             1 watt infrared lamp done clear
  C)
             50 watt ultraviolet lamp done clear
  D)
             1 watt ultraviolet lamp done clear
  E)
  (e)     Both (c) and (d) done clear
  View Solution play_arrow

• question_answer34)
  Threshold frequency for a metal is \[{{10}^{15}}\]Hz. Light of \[\lambda =4000{AA}\]falls on its surface. Which of the following statements is correct
  A)
  No photoelectric emission takes place done clear
  B)
  Photo-electrons come out with zero speed done clear
  C)
  Photo-electrons come out with 103 m/sec speed done clear
  D)
  Photo-electrons come out with 105 m/sec speed done clear
  View Solution play_arrow

• question_answer35)
  Photo cells are used for the
  A)
             Reproduction of pictures from the cinema film done clear
  B)
             Reproduction of sound from the cinema film done clear
  C)
             Automatic switching of street light done clear
  D)
             (b) and (c) both done clear
  View Solution play_arrow

• question_answer36)
  Einstein got Nobel prize on which of the following works [DCE 1995]
  A)
             Mass-energy relation done clear
  B)
             Special theory of relativity done clear
  C)
             Photoelectric equation done clear
  D)
     (a) and (b) both done clear
  View Solution play_arrow

• question_answer37)
  The photo-electrons emitted from a surface of sodium metal are such that                                         [MP PMT 1992]
  A)
             They all are of the same frequency done clear
  B)
             They have the same kinetic energy done clear
  C)
             They have the same de Broglie wavelength done clear
  D)
             They have their speeds varying from zero to a certain maximum done clear
  View Solution play_arrow

• question_answer38)
  A metal surface of work function 1.07 eV is irradiated with light of wavelength 332 nm. The retarding potential required to stop the escape of photo-electrons is        [MP PMT 1992]
  A)
             4.81 eV                                    done clear
  B)
             3.74 eV done clear
  C)
             2.66 eV                                    done clear
  D)
             1.07 eV done clear
  View Solution play_arrow

• question_answer39)
  In a photo cell, the photo-electrons emission takes place
  A)
             After \[{{10}^{1}}\] sec on incident of light rays done clear
  B)
             After \[{{10}^{3}}\]sec on incident of light rays done clear
  C)
             After \[{{10}^{6}}\]sec on incident of light rays done clear
  D)
             After \[{{10}^{8}}\]sec on incident of light rays done clear
  View Solution play_arrow

• question_answer40)
  When light falls on a metal surface, the maximum kinetic energy of the emitted photo-electrons depends upon [MP PMT 1989; MP PET 1992, 93]
  A)
             The time for which light falls on the metal done clear
  B)
             Frequency of the incident light done clear
  C)
             Intensity of the incident light done clear
  D)
             Velocity of the incident light done clear
  View Solution play_arrow

• question_answer41)
  The electrons are emitted in the photoelectric effect from a metal surface                                          [MP PET 1992]
  A)
             Only if the frequency of the incident radiation is above a certain threshold value done clear
  B)
             Only if the temperature of the surface is high done clear
  C)
             At a rate that is independent of the nature of the metal done clear
  D)
             With a maximum velocity proportional to the frequency of the incident radiation done clear
  View Solution play_arrow

• question_answer42)
  The work function of a metal is 4.2 eV, its threshold    wavelength will be                                               [BHU 2003; CPMT 2004]
  A)
          4000 Å                                         done clear
  B)
             3500 Å done clear
  C)
             2955 Å                                      done clear
  D)
             2500 Å done clear
  View Solution play_arrow

• question_answer43)
  The number of photo-electrons emitted per second from a metal surface increases when                    [EAMCET (Med.) 1995; CBSE PMT 1993; MP PMT 1994, 2002; MH CET 1999; KCET 2003]
  A)
             The energy of incident photons increases done clear
  B)
             The frequency of incident light increases done clear
  C)
             The wavelength of the incident light increases done clear
  D)
             The intensity of the incident light increases done clear
  View Solution play_arrow

• question_answer44)
  The work function of metal is 1 eV. Light of wavelength 3000 Å is incident on this metal surface. The velocity of emitted photo-electrons will be                       [MP PMT 1990]
  A)
             10 m/sec                                 done clear
  B)
             \[1\times {{10}^{3}}\]m/sec done clear
  C)
             \[1\times {{10}^{4}}m/\sec \]m/sec                               done clear
  D)
             \[1\times {{10}^{6}}m/\sec \]m/sec done clear
  View Solution play_arrow

• question_answer45)
  The retarding potential for having zero photo-electron current                                  [MP PMT/PET 1988]
  A)
             Is proportional to the wavelength of incident light done clear
  B)
             Increases uniformly with the increase in the wavelength of incident light done clear
  C)
             Is proportional to the frequency of incident light done clear
  D)
             Increases uniformly with the increase in the frequency of incident light wave done clear
  View Solution play_arrow

• question_answer46)
  In a dark room of photography, generally red light is used. The reason is
  A)
             Most of the photographic films are not sensitive to red light done clear
  B)
             The frequency for red light is low and hence the energy \[hv\]of photons is less done clear
  C)
             (a) and (b) both done clear
  D)
             None of the above done clear
  View Solution play_arrow

• question_answer47)
  The work function of a metal is \[1.6\times {{10}^{-19}}\]J. When the metal surface is illuminated by the light of wavelength  6400 Å, then the maximum kinetic energy of emitted photo-electrons will be (Planck's constant \[h=6.4\times {{10}^{-34}}Js\]) [MP PMT 1989]
  A)
             \[14\times {{10}^{-19}}\ J\]    done clear
  B)
             \[2.8\times {{10}^{-19}}\ J\] done clear
  C)
             \[1.4\times {{10}^{-19}}J\]      done clear
  D)
             \[1.4\times {{10}^{-19}}\,eV\] done clear
  View Solution play_arrow

• question_answer48)
  Ultraviolet radiations of \[6.2\,eV\] falls on an aluminium surface (work function \[4.2\ eV\]). The kinetic energy in joules of the fastest electron emitted is approximately [MNR 1987; MP PET 1990; CBSE PMT 1993; Pb. PMT 2001; BVP 2003; Pb. PET 2004]
  A)
             \[3.2\times {{10}^{-21}}\]       done clear
  B)
             \[3.2\times {{10}^{-19}}\] done clear
  C)
             \[3.2\times {{10}^{-17}}\]       done clear
  D)
             \[3.2\times {{10}^{-15}}\] done clear
  View Solution play_arrow

• question_answer49)
  The work function for tungsten and sodium are 4.5 eV and 2.3 eV respectively. If the threshold wavelength \[\lambda \] for sodium is \[5460{AA}\], the value of  \[\lambda \] for tungsten is [MP PET 1990]
  A)
  5893 Å                                      done clear
  B)
  10683 Å done clear
  C)
  2791 Å                                      done clear
  D)
  528 Å done clear
  View Solution play_arrow

• question_answer50)
  A photon of energy 3.4 eV is incident on a metal having work function 2 eV. The maximum K.E. of photo-electrons is equal to                                                     [MP PET 1991]
  A)
             1.4 eV                                       done clear
  B)
             1.7 eV done clear
  C)
             5.4 eV                                       done clear
  D)
             6.8 eV done clear
  View Solution play_arrow

• question_answer51)
  The work function of a metallic surface is 5.01 eV. The photo-electrons are emitted when light of wavelength 2000Å falls on it. The potential difference applied to stop the fastest photo-electrons is  \[[h=4.14\times {{10}^{-15}}\ eV\sec ]\] [MP PET 1991; DPMT 1999]
  A)
             1.2 volts                                  done clear
  B)
             2.24 volts done clear
  C)
             3.6 volts                                  done clear
  D)
             4.8 volts done clear
  View Solution play_arrow

• question_answer52)
  The photoelectric threshold wavelength for a metal surface is 6600 Å. The work function for this is           [MP PET 1991]
  A)
             1.87 V                                       done clear
  B)
             1.87 eV done clear
  C)
             18.7 eV                                    done clear
  D)
             0.18 eV done clear
  View Solution play_arrow

• question_answer53)
  Photoelectric effect was successfully explained first by
  A)
             Planck                                      done clear
  B)
             Hallwash done clear
  C)
             Hertz                                        done clear
  D)
             Einstein done clear
  View Solution play_arrow

• question_answer54)
  The spectrum of radiation \[1.0\times {{10}^{14}}Hz\] is in the infrared region. The energy of one photon of this in joules will be [MP PET 1982]
  A)
             \[6.62\times {{10}^{-48}}\]     done clear
  B)
             \[6.62\times {{10}^{-20}}\] done clear
  C)
             \[\frac{6.62}{3}\times {{10}^{-28}}\]                              done clear
  D)
             \[3\times 6.62\times {{10}^{-28}}\] done clear
  View Solution play_arrow

• question_answer55)
  A radio transmitter operates at a frequency of 880 kHz and a power of 10 kW. The number of photons emitted per second are                                          [CBSE PMT 1990; MP PET 1990]
  A)
             \[1.72\times {{10}^{31}}\]       done clear
  B)
             \[1327\times {{10}^{34}}\] done clear
  C)
             \[13.27\times {{10}^{34}}\]    done clear
  D)
             \[0.075\times {{10}^{-34}}\] done clear
  View Solution play_arrow

• question_answer56)
  A photo cell is receiving light from a source placed at a distance of 1 m. If the same source is to be placed at a distance of 2 m, then the ejected electron [MNR 1986; UPSEAT 2000, 01]
  A)
             Moves with one-fourth energy as that of the initial energy done clear
  B)
             Moves with one-fourth of momentum as that of the initial momentum done clear
  C)
             Will be half in number done clear
  D)
             Will be one-fourth in number done clear
  View Solution play_arrow

• question_answer57)
  In a photoelectric experiment for 4000 Å incident radiation, the potential difference to stop the ejection is 2 V. If the incident light is changed to 3000 Å, then the potential required to stop the ejection of electrons will be [MP PET 1995]
  A)
             2 V done clear
  B)
             Less than 2 V done clear
  C)
             Zero                                          done clear
  D)
             Greater than 2 V done clear
  View Solution play_arrow

• question_answer58)
  Light of wavelength 4000 Å is incident on a sodium surface for which the threshold wave length of photo ? electrons is 5420 Å. The work function of sodium is  [MP PMT 1993; Pb. PMT 2002]
  A)
             4.58 eV                                    done clear
  B)
             2.29 eV                                    done clear
  C)
             1.14 eV                                    done clear
  D)
             0.57 eV done clear
  View Solution play_arrow

• question_answer59)
  Photo cell is a device to                                            [MP PET 1993]
  A)
             Store photons                      done clear
  B)
             Measure light intensity    done clear
  C)
             Convert photon energy into mechanical energy done clear
  D)
             Store electrical energy for replacing storage batteries done clear
  View Solution play_arrow

• question_answer60)
  If the work function for a certain metal is \[3.2\times {{10}^{-19}}\]joule and it is illuminated with light of frequency \[8\times {{10}^{14}}\]Hz. The maximum kinetic energy of the photo-electrons would be [MP PET 1993]
  A)
             \[2.1\times {{10}^{-19}}J\]      done clear
  B)
             \[8.5\times {{10}^{-19}}J\] done clear
  C)
             \[5.3\times {{10}^{-19}}J\]      done clear
  D)
             \[3.2\times {{10}^{-19}}J\] \[(h=6.63\times {{10}^{-34}}Js)\] done clear
  View Solution play_arrow

• question_answer61)
  Stopping potential for photoelectrons              [MP PET 1994]
  A)
             Does not depend on the frequency of the incident light done clear
  B)
             Does not depend upon the nature of the cathode material done clear
  C)
             Depends on both the frequency of the incident light and nature of the cathode material done clear
  D)
             Depends upon the intensity of the incident light done clear
  View Solution play_arrow

• question_answer62)
  The maximum wavelength of radiation that can produce photoelectric effect in a certain metal is 200 nm. The maximum kinetic energy acquired by electron due to radiation of wavelength 100 nm will be           [MP PMT 1994]
  A)
             12.4 eV                                    done clear
  B)
             6.2 eV done clear
  C)
             100 eV                                      done clear
  D)
             200 eV done clear
  View Solution play_arrow

• question_answer63)
  When the light source is kept 20 cm away from a photo cell, stopping potential 0.6 V is obtained. When source is kept 40 cm away, the stopping potential will be    [MP PMT 1994]
  A)
             0.3 V                                         done clear
  B)
             0.6 V done clear
  C)
             1.2 V                                         done clear
  D)
             2.4 V done clear
  View Solution play_arrow

• question_answer64)
  The minimum energy required to remove an electron is called   [AFMC 1995; DPMT 2001]
  A)
             Stopping potential              done clear
  B)
             Kinetic energy done clear
  C)
             Work function                      done clear
  D)
             None of these                      done clear
  View Solution play_arrow

• question_answer65)
  Light of wavelength 4000 Å falls on a photosensitive metal and a negative 2V potential stops the emitted electrons. The work function of the material (in eV) is approximately            \[(h=6.6\times {{10}^{-34}}Js,\ \ e=1.6\times {{10}^{-19}}C,\ \ c=3\times {{10}^{8}}m{{s}^{-1}})\]  [MP PMT 1995; MH CET 2004]
  A)
             1.1  done clear
  B)
             2.0 done clear
  C)
             2.2  done clear
  D)
             3.1 done clear
  View Solution play_arrow

• question_answer66)
  Assuming photoemission to take place, the factor by which the maximum velocity of the emitted photoelectrons changes when the wavelength of the incident radiation is increased four times, is                            [Haryana CEE 1996]
  A)
             4     done clear
  B)
             \[\frac{1}{4}\] done clear
  C)
             2     done clear
  D)
             \[\frac{1}{2}\] done clear
  View Solution play_arrow

• question_answer67)
  Work function of a metal is 2.51 eV. Its threshold frequency is                    [MP PET 1996; Pb. PET 2003]
  A)
             \[5.9\times {{10}^{14}}\]cycle/sec                                   done clear
  B)
             \[6.5\times {{10}^{14}}cycle/\sec \]cycle/sec done clear
  C)
             \[9.4\times {{10}^{14}}cycle/\sec \]cycle/sec             done clear
  D)
             \[6.08\times {{10}^{14}}\] cycle/sec done clear
  View Solution play_arrow

• question_answer68)
  Energy conversion in a photoelectric cell takes place from             [AFMC 1993; MP PET 1996; MP PMT 1996]
  A)
             Chemical to electrical        done clear
  B)
             Magnetic to electrical done clear
  C)
             Optical to electrical             done clear
  D)
             Mechanical to electrical done clear
  View Solution play_arrow

• question_answer69)
  Which one of the following is true in photoelectric emission [MP PMT 1996; JIPMER 2001, 02]
  A)
             Photoelectric current is directly proportional to the amplitude of light of a given frequency done clear
  B)
             Photoelectric current is directly proportional to the intensity of light of a given frequency at moderate intensities done clear
  C)
             Above the threshold frequency, the maximum K.E. of photoelectrons is inversely proportional to the frequency of incident light done clear
  D)
             The threshold frequency depends upon the wavelength of incident light done clear
  View Solution play_arrow

• question_answer70)
  When a point source of light is at a distance of one metre from a photo cell, the cut off voltage is found to be V. If the same source is placed at 2 m distance from photo cell, the cut off voltage will be
  A)
             V     done clear
  B)
             V/2 done clear
  C)
             V/4 done clear
  D)
             \[V/\sqrt{2}\] done clear
  View Solution play_arrow

• question_answer71)
  The work function of a photoelectric material is 3.3 eV. The threshold frequency will be equal to               [UPSEAT 1999]
  A)
             \[8\times {{10}^{4}}Hz\]  done clear
  B)
             \[8\times {{10}^{56}}Hz\] done clear
  C)
             \[8\times {{10}^{10}}Hz\]        done clear
  D)
             \[8\times {{10}^{14}}Hz\] done clear
  View Solution play_arrow

• question_answer72)
  If the work function of a metal is \['\varphi '\] and the frequency of the incident light is \['\nu '\], there is no emission of photoelectron if
  A)
             \[\nu <\frac{\varphi }{h}\]      done clear
  B)
             \[\nu =\frac{\varphi }{h}\] done clear
  C)
             \[\nu >\frac{\varphi }{h}\]      done clear
  D)
             \[\nu >\ =\ <\frac{\varphi }{h}\] done clear
  View Solution play_arrow

• question_answer73)
  A photoelectric cell is illuminated by a point source of light 1 m away. When the source is shifted to 2 m then [CBSE PMT 2003]
  A)
             Number of electrons emitted is half the initial number done clear
  B)
             Each emitted electron carries half the initial energy done clear
  C)
             Number of electrons emitted is a quarter of the initial number done clear
  D)
             Each emitted electron carries one quarter of the initial energy done clear
  View Solution play_arrow

• question_answer74)
  Light of wavelength \[\lambda \]strikes a photo-sensitive surface and electrons are ejected with kinetic energy E. If  the kinetic energy is to be increased to 2E, the wavelength must be changed to \[\lambda '\] where                                          [MP PET 1997]
  A)
             \[\lambda '=\frac{\lambda }{2}\]                                     done clear
  B)
             \[\lambda '=2\lambda \] done clear
  C)
             \[\frac{\lambda }{2}<\lambda '<\lambda \]                done clear
  D)
             \[\lambda '>\lambda \] done clear
  View Solution play_arrow

• question_answer75)
  If in a photoelectric experiment, the wavelength of incident radiation is reduced from 6000 Å to 4000 Å then                 [MP PMT 1999]
  A)
             Stopping potential will decrease done clear
  B)
             Stopping potential will increase done clear
  C)
             Kinetic energy of emitted electrons will decrease done clear
  D)
             The value of work function will decrease done clear
  View Solution play_arrow

• question_answer76)
  The photoelectric work function for a metal surface is 4.125 eV. The cut-off wavelength for this surface is             [CBSE PMT 1999; KCET 2001]
  A)
             4125 Å                                      done clear
  B)
             2062.5 Å done clear
  C)
             3000 Å                                      done clear
  D)
             6000 Å done clear
  View Solution play_arrow

• question_answer77)
  As the intensity of incident light increases [CPMT 1999; CBSE PMT 1999; MH CET (Med.) 2000; KCET (Engg./Med.) 2001; Pb. PET 2001]
  A)
             Photoelectric current increases done clear
  B)
             Photoelectric current decreases done clear
  C)
             Kinetic energy of emitted photoelectrons increases done clear
  D)
             Kinetic energy of emitted photoelectrons decreases done clear
  View Solution play_arrow

• question_answer78)
  Light of wavelength 5000 Å falls on a sensitive plate with photoelectric work function of 1.9 eV. The kinetic energy of the photoelectron emitted will be                  [CBSE PMT 1998]
  A)
             0.58 eV                                    done clear
  B)
             2.48 eV done clear
  C)
             1.24 eV                                    done clear
  D)
             1.16 eV done clear
  View Solution play_arrow

• question_answer79)
  Which of the following is dependent on the intensity of incident radiation in a photoelectric experiment [AIIMS 1998]
  A)
             Work function of the surface done clear
  B)
             Amount of photoelectric current done clear
  C)
             Stopping potential will be reduced done clear
  D)
             Maximum kinetic energy of photoelectrons done clear
  View Solution play_arrow

• question_answer80)
  The work function of a substance is 4.0 eV. The longest wavelength of light that can cause photoelectron emission from this substance is approximately [IIT JEE 1998; UPSEAT 2002, 03; AIEEE 2004]
  A)
             540 nm                                    done clear
  B)
             400 nm done clear
  C)
             310 nm                                    done clear
  D)
             220 nm done clear
  View Solution play_arrow

• question_answer81)
  The maximum kinetic energy of photoelectrons emitted from a surface when photons of energy 6 eV fall on it is 4 eV. The stopping potential in volts is [IIT JEE 1997 Re-Exam]
  A)
             2     done clear
  B)
             4 done clear
  C)
             6     done clear
  D)
             10 done clear
  View Solution play_arrow

• question_answer82)
  Work function of a metal is 2.1 eV. Which of the waves of the following wavelengths will be able to emit photoelectrons from its surface                                      [Bihar MEE 1995]
  A)
             4000 Å, 7500 Å                      done clear
  B)
             5500 Å, 6000 Å done clear
  C)
             4000 Å, 6000 Å                      done clear
  D)
             None of these done clear
  View Solution play_arrow

• question_answer83)
  If mean wavelength of light radiated by 100 W lamp is 5000 Å, then number of photons radiated per second are [RPET 1997]
  A)
             \[3\times {{10}^{23}}\]     done clear
  B)
             \[2.5\times {{10}^{22}}\] done clear
  C)
             \[2.5\times {{10}^{20}}\] done clear
  D)
             \[5\times {{10}^{17}}\] done clear
  View Solution play_arrow

• question_answer84)
  The frequency of the incident light falling on a photosensitive metal plate is doubled, the kinetic energy of the emitted photoelectrons is                                                      [Roorkee 1992]
  A)
             Double the earlier value  done clear
  B)
             Unchanged done clear
  C)
             More than doubled           done clear
  D)
             Less than doubled done clear
  View Solution play_arrow

• question_answer85)
  When light of wavelength 300 nm (nanometer) falls on a photoelectric emitter, photoelectrons are liberated. For another emitter, however light of 600 nm wavelength is sufficient for creating photoemission. What is the ratio of the work functions of the two emitter [CBSE PMT 1993; JIPMER 2000]
  A)
             1 : 2                                           done clear
  B)
             2 : 1 done clear
  C)
             4 : 1                                           done clear
  D)
             1 : 4 done clear
  View Solution play_arrow

• question_answer86)
  Threshold wavelength for photoelectric effect on sodium is 5000 Å. Its work function is [CBSE PMT 1993]
  A)
             15 J done clear
  B)
             \[16\times {{10}^{-14}}J\] done clear
  C)
             \[4\times {{10}^{-19}}J\]  done clear
  D)
             \[4\times {{10}^{-81}}J\] done clear
  View Solution play_arrow

• question_answer87)
  The cathode of a photoelectric cell is changed such that the work function changes from W1 to W2 (W2>W1). If the current before and after change are I1 and I2, all other conditions remaining unchanged, then (assuming hn > W2) [CBSE PMT 1992]
  A)
             \[{{I}_{1}}={{I}_{2}}\]        done clear
  B)
             \[{{I}_{1}}<{{I}_{2}}\] done clear
  C)
             \[{{I}_{1}}>{{I}_{2}}\]        done clear
  D)
             \[{{I}_{1}}<{{I}_{2}}<2{{I}_{1}}\] done clear
  View Solution play_arrow

• question_answer88)
  A beam of light of wavelength \[\lambda \] and with illumination L falls on a clean surface of sodium. If N photoelectrons are emitted each with kinetic energy E, then      [BHU 1994]
  A)
             \[N\propto L\] and \[E\propto L\]                                   done clear
  B)
    \[N\propto L\]and \[E\propto \frac{1}{\lambda }\] done clear
  C)
             \[N\propto \lambda \] and \[E\propto L\]                   done clear
  D)
             \[N\propto \frac{1}{\lambda }\]and \[E\propto \frac{1}{L}\] done clear
  View Solution play_arrow

• question_answer89)
  Which of the following statements is correct [CBSE PMT 1997]
  A)
             The current in a photocell increases with increasing frequency of light done clear
  B)
             The photocurrent is proportional to applied voltage done clear
  C)
             The photocurrent increases with increasing intensity of light done clear
  D)
             The stopping potential increases with increasing intensity of incident light done clear
  View Solution play_arrow

• question_answer90)
  What is the stopping potential when the metal with work function 0.6 eV is illuminated with the light of 2 eV [BHU 1998; MH CET 2003]
  A)
             2.6 V                                         done clear
  B)
             3.6 V done clear
  C)
             0.8 V                                         done clear
  D)
             1.4 V done clear
  View Solution play_arrow

• question_answer91)
  When yellow light is incident on a surface, no electrons are emitted while green light can emit. If red light is incident on the surface, then       [MNR 1998; MP PET 2000; MH CET 2000]
  A)
             No electrons are emitted done clear
  B)
             Photons are emitted done clear
  C)
             Electrons of higher energy are emitted done clear
  D)
             Electrons of lower energy are emitted done clear
  View Solution play_arrow

• question_answer92)
  The photoelectric threshold wavelength of a certain metal is 3000Å. If the radiation of 2000Å is incident on the metal [MNR 1998; KCET 1994]
  A)
             Electrons will be emitted done clear
  B)
             Positrons will be emitted done clear
  C)
             Protons will be emitted done clear
  D)
             Electrons will not be emitted done clear
  View Solution play_arrow

• question_answer93)
  A photocell stops emission if it is maintained at 2V negative potential. The energy of most energetic photoelectron is  [JIPMER 1999]
  A)
             2eV                                           done clear
  B)
             2J done clear
  C)
             2kJ done clear
  D)
             2keV done clear
  View Solution play_arrow

• question_answer94)
  The work functions for sodium and copper are \[2eV\] and \[4eV\]. Which of them is suitable for a photocell with 4000 Å light                                                    [RPET 1999]
  A)
             Copper                                    done clear
  B)
             Sodium done clear
  C)
             Both                                         done clear
  D)
             Neither of them done clear
  View Solution play_arrow

• question_answer95)
  For intensity I of a light of wavelength 5000Å the photoelectron saturation current is 0.40 \[\mu \,A\] and stopping potential is 1.36 V, the work function of metal is  [RPET 1999]
  A)
             2.47 eV                                    done clear
  B)
             1.36 eV done clear
  C)
             1.10 eV                                    done clear
  D)
             0.43 eV done clear
  View Solution play_arrow

• question_answer96)
  The work function of aluminium is 4.2 \[eV.\] If two photons, each of energy 3.5 \[eV\]strike an electron of aluminium, then emission of electrons will be                                                      [AFMC 1999]
  A)
             Possible done clear
  B)
             Not possible done clear
  C)
             Data is incomplete done clear
  D)
             Depend upon the density of the surface done clear
  View Solution play_arrow

• question_answer97)
  In photoelectric effect if the intensity of light is doubled then maximum kinetic energy of photoelectrons will become            [RPMT 1999]
  A)
             Double                                    done clear
  B)
             Half done clear
  C)
             Four time                               done clear
  D)
             No change done clear
  View Solution play_arrow

• question_answer98)
  Energy required to remove an electron from aluminium surface is 4.2 eV. If light of wavelength 2000 Å falls on the surface, the velocity of the fastest electron ejected from the surface will be                                       [AMU 1999]
  A)
             \[8.4\times {{10}^{5}}m/sec\]                                           done clear
  B)
             \[7.4\times {{10}^{5}}m/sec\] done clear
  C)
             \[6.4\times {{10}^{5}}m/sec\]                                           done clear
  D)
             \[8.4\times {{10}^{6}}m/sec\] done clear
  View Solution play_arrow

• question_answer99)
  Mercury violet light \[(\lambda =4558{AA})\] is falling on a photosensitive material \[(\varphi =2.5eV)\]. The speed of the ejected electrons is in \[m{{s}^{-1}}\], about                         [AMU (Engg.) 1999]
  A)
  \[3\times {{10}^{5}}\]       done clear
  B)
  \[{{K}_{A}}={{K}_{B}}/2\] done clear
  C)
  \[4\times {{10}^{4}}\]       done clear
  D)
  \[3.65\times {{10}^{7}}\] done clear
  View Solution play_arrow

• question_answer100)
  The work functions of metals A and B are in the ratio 1 : 2. If light of frequencies \[f\] and \[2f\] are incident on the surfaces of A and B respectively, the ratio of the maximum kinetic energies of photoelectrons emitted is (f is greater than threshold frequency of A, 2f is greater than threshold frequency of B)                                         [EAMCET (Med.) 2000]
  A)
             1 : 1                                           done clear
  B)
             1 : 2 done clear
  C)
             1 : 3                                           done clear
  D)
             1 : 4 done clear
  View Solution play_arrow

• question_answer101)
  Light of frequency n is incident on a substance of threshold frequency n0(n0 < n). The energy of the emitted photo-electron will be                                                      [MP PET 2000; 03]
  A)
             \[h(\nu -{{\nu }_{0}})\]    done clear
  B)
             \[h/\nu \] done clear
  C)
             \[he\,(\nu -{{\nu }_{0}})\]      done clear
  D)
             \[h/{{\nu }_{0}}\] done clear
  View Solution play_arrow

• question_answer102)
  The stopping potential \[({{V}_{0}})\]                                         [BHU 2000]
  A)
             Depends upon the angle of incident light done clear
  B)
             Depends upon the intensity of incident light done clear
  C)
             Depends upon the surface nature of the substance done clear
  D)
             Is independent of the intensity of the incident light done clear
  View Solution play_arrow

• question_answer103)
  If work function of metal is 3\[eV\] then threshold wavelength will be                     [RPMT 2000]
  A)
             4125 Å                                      done clear
  B)
             4000 Å done clear
  C)
             4500 Å                                      done clear
  D)
             5000 Å done clear
  View Solution play_arrow

• question_answer104)
  When wavelength of incident photon is decreased then [RPET 2000]
  A)
             Velocity of emitted photo-electron decreases done clear
  B)
             Velocity of emitted photoelectron increases done clear
  C)
             Velocity of photoelectron do not charge done clear
  D)
             Photo electric current increases done clear
  View Solution play_arrow

• question_answer105)
  Quantam nature of light is explained by which of the following phenomenon                        [RPET 2000]
  A)
             Huygen wave theory done clear
  B)
             Photoelectric effect done clear
  C)
             Maxwell electromagnetic theory done clear
  D)
             de-Broglie theory done clear
  View Solution play_arrow

• question_answer106)
  When a metal surface is illuminated by light of wavelengths 400 nm and 250 nm, the maximum velocities of the photoelectrons ejected are \[v\] and \[2v\] respectively. The work function of the metal is (h = Planck?s constant, c = velocity of light in air)                                    [EAMCET (Engg.) 2000]
  A)
             \[2\,hc\,\times {{10}^{6}}\,J\]                                           done clear
  B)
             \[1.5\,hc\,\times {{10}^{6}}\,J\] done clear
  C)
             \[hc\,\times {{10}^{6}}\,J\]    done clear
  D)
             \[0.5\,\,hc\,\times {{10}^{6}}\,J\] done clear
  View Solution play_arrow

• question_answer107)
  4 eV is the energy of the incident photon and the work function in \[2eV.\] What is the stopping potential           [DCE 2000; AIIMS 2004]
  A)
             2V  done clear
  B)
             4V done clear
  C)
             6V  done clear
  D)
             \[2\sqrt{2}V\] done clear
  View Solution play_arrow

• question_answer108)
  Light of frequency n is incident on a certain photoelectric substance with threshold frequency n0. The work function for the substance is                                                 [MP PMT 2001]
  A)
             hn  done clear
  B)
             hn0 done clear
  C)
             \[h(\nu -{{\nu }_{0}})\]    done clear
  D)
             \[h(\nu +{{\nu }_{0}})\] done clear
  View Solution play_arrow

• question_answer109)
  If threshold wavelength for sodium is 6800Å then the work function will be         [RPET 2001]
  A)
             \[1.8eV\]                                done clear
  B)
             \[2.5eV\] done clear
  C)
             \[2.1eV\]                                done clear
  D)
             \[1.4eV\] done clear
  View Solution play_arrow

• question_answer110)
  If intensity of incident light is increased in PEE then which of the following is true                                              [RPET 2001]
  A)
             Maximum K.E. of ejected electron will increase done clear
  B)
             Work function will remain unchanged done clear
  C)
             Stopping potential will decrease done clear
  D)
             Maximum K.E. of ejected electron will decrease done clear
  View Solution play_arrow

• question_answer111)
  Light of frequency \[8\times {{10}^{15}}Hz\] is incident on a substance of photoelectric work function \[6.125\,eV.\] The maximum kinetic energy of the emitted photoelectrons is [AFMC 2001]
  A)
             17\[eV\]                                 done clear
  B)
             22\[eV\] done clear
  C)
             27\[eV\]                                 done clear
  D)
             37\[eV\] done clear
  View Solution play_arrow

• question_answer112)
  The photoelectric threshold wavelength for potassium (work function being \[2eV\]) is [CPMT 2001]
  A)
             310 nm                                    done clear
  B)
             620 nm done clear
  C)
             1200 nm                                  done clear
  D)
             2100 nm done clear
  View Solution play_arrow

• question_answer113)
  Photons of energy 6 eV are incident on a metal surface whose work function is 4 eV. The minimum kinetic energy of the emitted photo-electrons will be                  [MP PET 2001]
  A)
             0 eV                                          done clear
  B)
             1 eV done clear
  C)
             2 eV                                          done clear
  D)
             10 eV done clear
  View Solution play_arrow

• question_answer114)
  According to photon theory of light which of the following physical quantities associated with a photon do not/does not change as it collides with an electron in vacuum [AMU (Engg.) 2001]
  A)
             Energy and momentum   done clear
  B)
             Speed and momentum done clear
  C)
             Speed only                            done clear
  D)
             Energy only done clear
  View Solution play_arrow

• question_answer115)
  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)
             \[4\times {{10}^{10}}Hz\]        done clear
  B)
             \[4\times {{10}^{11}}Hz\] done clear
  C)
             \[4\times {{10}^{14}}Hz\]        done clear
  D)
             \[4\times {{10}^{-10}}Hz\] done clear
  View Solution play_arrow

• question_answer116)
  Light of two different frequencies whose photons have energies \[1eV\] and \[2.5eV\] respectively, successively illuminates a metal of work function \[0.5eV\]. The ratio of maximum kinetic energy of the emitted electron will be [AIEEE 2002]
  A)
             1 : 5                                           done clear
  B)
             1 : 4 done clear
  C)
             1 : 2                                           done clear
  D)
             1 : 1 done clear
  View Solution play_arrow

• question_answer117)
  Sodium and copper have work functions 2.3\[eV\]and 4.5\[eV\] respectively. Then the ratio of their threshold wavelengths is nearest to                                         [AIEEE 2002]
  A)
             1: 2 done clear
  B)
             4 : 1 done clear
  C)
             2 : 1                                           done clear
  D)
             1 : 4 done clear
  View Solution play_arrow

• question_answer118)
  Photon of 5.5 eV energy fall on the surface of the metal emitting photoelectrons of maximum kinetic energy 4.0 eV. The stopping voltage required for these electrons are [Orissa (Engg.) 2002; DPMT 2004]
  A)
             5.5\[V\]                                   done clear
  B)
             1.5\[V\] done clear
  C)
             9.5\[V\]                                   done clear
  D)
             4.0\[V\] done clear
  View Solution play_arrow

• question_answer119)
  A caesium photocell, with a steady potential difference of 60V across, is illuminated by a bright point source of light 50 cm away. When the same light is placed 1m away the photoelectrons emitted from the cell        [KCET 2002]
  A)
             Are one quarter as numerous done clear
  B)
             Are half as numerous done clear
  C)
             Each carry one quarter of their previous momentum done clear
  D)
             Each carry one quarter of their previous energy done clear
  View Solution play_arrow

• question_answer120)
  A radio transmitter radiates 1 kW power at a wavelength 198.6 metres. How many photons does it emit per second [Kerala (Engg.) 2002]
  A)
             \[{{10}^{10}}\]                      done clear
  B)
             \[{{10}^{20}}\] done clear
  C)
             \[{{10}^{30}}\]                      done clear
  D)
             \[{{10}^{40}}\] done clear
  View Solution play_arrow

• question_answer121)
  The number of photons of wavelength 540 nm emitted per second by an electric bulb of power 100W is (taking h = \[6\times {{10}^{-34}}\,J\text{-}sec\]) [Kerala (Engg.) 2002; Pb. PET 2001]
  A)
             100 done clear
  B)
             1000 done clear
  C)
             \[3\times {{10}^{20}}\]     done clear
  D)
             \[3\times {{10}^{18}}\] done clear
  View Solution play_arrow

• question_answer122)
  When radiation is incident on a photoelectron emitter, the stopping potential is found to be 9 volts. If \[e/m\] for the electron is \[1.8\times {{10}^{11}}\,C\,k{{g}^{-1}}\] the maximum velocity of the ejected electrons is                      [Kerala (Engg.) 2002]
  A)
             \[6\times {{10}^{5}}\,m{{s}^{-1}}\]                                 done clear
  B)
             \[8\times {{10}^{5}}\,m{{s}^{-1}}\] done clear
  C)
             \[1.8\times {{10}^{6}}\,m{{s}^{-1}}\]                             done clear
  D)
             \[1.8\times {{10}^{5}}\,m{{s}^{-1}}\] done clear
  View Solution play_arrow

• question_answer123)
  The threshold wavelength for photoelectric effect of a metal is 6500 Å. The work function of the metal is approximately                   [MP PMT 2002]
  A)
             2 eV                                          done clear
  B)
             1 eV done clear
  C)
             0.1\[eV\]                                done clear
  D)
             3 eV done clear
  View Solution play_arrow

• question_answer124)
  When ultraviolet rays are incident on metal plate, then photoelectric effect does not occurs. It occurs by the incidence of               [CBSE PMT 2002; DCE 1997; AIIMS 2004]
  A)
             X-rays                                      done clear
  B)
             Radio wave done clear
  C)
             Infrared rays                         done clear
  D)
             Greenhouse effect done clear
  View Solution play_arrow

• question_answer125)
  Light of frequency 4n0 is incident on the metal of the threshold frequency n0. The maximum kinetic energy of the emitted photoelectrons is                                      [MP PET 2002]
  A)
             \[3\,h{{\nu }_{0}}\]            done clear
  B)
             \[2\,h{{\nu }_{0}}\] done clear
  C)
             \[\frac{3}{2}\,h{{\nu }_{0}}\] done clear
  D)
             \[\frac{1}{2}h{{\nu }_{0}}\] done clear
  View Solution play_arrow

• question_answer126)
  By photoelectric effect, Einstein, proved         [MP PET 2003]
  A)
             \[E=hv\]                                  done clear
  B)
             \[K.E.=\frac{1}{2}m{{v}^{2}}\] done clear
  C)
             \[E=m{{c}^{2}}\]                  done clear
  D)
             \[E=\frac{Rh{{c}^{2}}}{{{n}^{2}}}\] done clear
  View Solution play_arrow

• question_answer127)
  The work function of sodium is 2.3 eV. The threshold wavelength of sodium will be                         [BHU 2003]
  A)
             2900 Å                                      done clear
  B)
             2500 Å done clear
  C)
             5380 Å                                      done clear
  D)
             2000 Å done clear
  View Solution play_arrow

• question_answer128)
  Which of the following shown particle nature of light [AFMC 2003; CBSE PMT 2001]
  A)
             Refraction                              done clear
  B)
             Interference done clear
  C)
             Polarization                           done clear
  D)
             Photoelectric effect done clear
  View Solution play_arrow

• question_answer129)
  Two identical photo-cathodes receive light of frequencies \[{{f}_{1}}\] and \[{{f}_{2}}\]. If the velocities of the photo electrons (of mass \[m\]) coming out are respectively \[{{v}_{1}}\] and \[{{v}_{2}}\], then            [AIEEE 2003]
  A)
             \[{{v}_{1}}-{{v}_{2}}={{\left[ \frac{2h}{m}\left( {{f}_{1}}-{{f}_{2}} \right) \right]}^{1/2}}\] done clear
  B)
             \[v_{1}^{2}-v_{2}^{2}=\frac{2h}{m}\left( {{f}_{1}}-{{f}_{2}} \right)\] done clear
  C)
             \[{{v}_{1}}+{{v}_{2}}={{\left[ \frac{2h}{m}\left( {{f}_{1}}+{{f}_{2}} \right) \right]}^{1/2}}\] done clear
  D)
             \[v_{1}^{2}+v_{2}^{2}=\frac{2h}{m}\left( {{f}_{1}}+{{f}_{2}} \right)\] done clear
  View Solution play_arrow

• question_answer130)
  Consider the two following statements A and B and identify the correct choice given in the answers;            In photovlotaic cells the photoelectric current produced is not proportional to the, intensity of incident light.            In gas filled photoemissive cells, the velocity of photoelectrons depends on the wavelength of the incident radiation.                                                           [EAMCET (Engg.) 2003]
  A)
             Both A and B are true        done clear
  B)
             Both A and B are false done clear
  C)
             A is true but B is false        done clear
  D)
             A is false B is true done clear
  View Solution play_arrow

• question_answer131)
  When radiation of wavelength \[\lambda \] is incident on a metallic surface, the stopping potential is 4.8 volts. If the same surface is illuminated with radiation of double the wavelength, then the stopping potential becomes 1.6 volts. Then the threshold wavelength for the surface is  [EAMCET (Engg.) 2003]
  A)
             \[2\lambda \]                       done clear
  B)
             \[4\lambda \] done clear
  C)
             \[6\lambda \]                       done clear
  D)
             \[8\lambda \] done clear
  View Solution play_arrow

• question_answer132)
  The frequency and work function of an incident photon are n and \[{{\varphi }_{0}}\]. If n­0 is the threshold frequency then necessary condition for the emission of photo electron is [RPET 2003]
  A)
             \[\nu <{{\nu }_{0}}\]         done clear
  B)
             \[\nu =\frac{{{\nu }_{0}}}{2}\] done clear
  C)
             \[\nu \ge {{\nu }_{0}}\]    done clear
  D)
             None of these done clear
  View Solution play_arrow

• question_answer133)
  Light of wavelength 1824 Å, incident on the surface of a metal, produces photo-electrons with maximum energy 5.3 eV. When light of wavelength 1216 Å is used, the maximum energy of photoelectrons is 8.7 eV. The work function of the metal surface is                                                 [MP PMT 2004]
  A)
             3.5 eV                                       done clear
  B)
             13.6 eV done clear
  C)
             6.8 eV                                       done clear
  D)
             1.5 eV done clear
  View Solution play_arrow

• question_answer134)
  If the energy of a photon corresponding to a wavelength of 6000 Å is \[3.32\times {{10}^{-19}}J\], the photon energy for a wavelength of 4000 Å will be                                                            [DPMT 2004]
  A)
             1.4 eV                                       done clear
  B)
             4.9 eV done clear
  C)
             3.1 eV                                       done clear
  D)
             1.6 eV done clear
  View Solution play_arrow

• question_answer135)
  If the wavelength of light is 4000 Å, then the number of waves in 1 mm length will be     [J & K CET 2004]
  A)
             25   done clear
  B)
             0.25 done clear
  C)
             \[0.25\times {{10}^{4}}\] done clear
  D)
             \[25\times {{10}^{4}}\] done clear
  View Solution play_arrow

• question_answer136)
  The velocity of photon is proportional to (where n is frequency)                                               [Pb. PMT 2004]
  A)
             \[\frac{{{\nu }^{2}}}{2}\]  done clear
  B)
             \[\frac{1}{\sqrt{\nu }}\] done clear
  C)
             \[\sqrt{\nu }\]                      done clear
  D)
             n done clear
  View Solution play_arrow

• question_answer137)
  If the work function of a photometal is 6.825 eV. Its threshold wavelength will be \[(c=3\times {{10}^{8}}\,m/s)\] [Pb. PET 2000; BHU 2004]
  A)
             1200 Å                                      done clear
  B)
             1800 Å done clear
  C)
             2400 Å                                      done clear
  D)
             3600 Å done clear
  View Solution play_arrow

• question_answer138)
  A photon of energy 8 eV is incident on a metal surface of threshold frequency \[1.6\times {{10}^{15}}\,Hz\], then the maximum kinetic energy of photoelectrons emitted is \[(h=6.6\times {{10}^{-34}}\,Js)\]                                               [Pb. PET 2002]
  A)
             4.8 eV                                       done clear
  B)
             2.4 eV done clear
  C)
             1.4 eV                                       done clear
  D)
             0.8 eV done clear
  View Solution play_arrow

• question_answer139)
  If the energy of the photon is increased by a factor of 4, then its momentum                                      [UPSEAT 2004]
  A)
             Does not change done clear
  B)
             Decreases by a factor of 4 done clear
  C)
             Increases by a factor of 4 done clear
  D)
             Decreases by a factor of 2 done clear
  View Solution play_arrow

• question_answer140)
  The ratio of the energy of a photon with \[\lambda =150\,nm\] to that with \[\lambda =300\,nm\] is                                         [DCE 2003]
  A)
             2     done clear
  B)
             1/4 done clear
  C)
             4     done clear
  D)
             1/2 done clear
  View Solution play_arrow

• question_answer141)
  Photo-electric effect can be explained by             [DCE 2003]
  A)
             Corpusular theory of light       done clear
  B)
             Wave nature of light done clear
  C)
             Bohr?s theory                       done clear
  D)
             Quantum theory of light done clear
  View Solution play_arrow

• question_answer142)
  In photoelectric effect, the K.E. of electrons emitted from the metal surface depends upon                        [DCE 2003]
  A)
             Intensity of light done clear
  B)
             Frequency of incident light done clear
  C)
             Velocity of incident light done clear
  D)
             Both intensity and velocity of light done clear
  View Solution play_arrow

• question_answer143)
  The photoelectric effect can be understood on the basis of [Pb. PET 2004]
  A)
             The principle of superposition done clear
  B)
             The electromagnetic theory of light done clear
  C)
             The special theory of relativity done clear
  D)
             Line spectrum of the atom done clear
  View Solution play_arrow

• question_answer144)
  If the threshold wavelength for sodium is 5420 Å, then the work function of sodium is   [RPMT 2003]
  A)
             4.58 eV                                    done clear
  B)
             2.28 eV done clear
  C)
             1.14 eV                                    done clear
  D)
             0.23 eV done clear
  View Solution play_arrow

• question_answer145)
  The work function of a metal is                               [RPMT 2004]
  A)
             The energy for the electron to enter into the metal done clear
  B)
             The energy for producing X-ray done clear
  C)
             The energy for the electron to come out from metal surface done clear
  D)
             None of these done clear
  View Solution play_arrow

• question_answer146)
  The minimum wavelength of photon is 5000 Å, its energy will be                                               [RPMT 2004]
  A)
             2.5 eV                                       done clear
  B)
             50 V done clear
  C)
             5.48 eV                                    done clear
  D)
             7.48 eV done clear
  View Solution play_arrow

• question_answer147)
  Which of one is correct                                                  [DCE 1998]
  A)
             \[{{E}^{2}}={{p}^{2}}{{c}^{2}}\]                                         done clear
  B)
             \[{{E}^{2}}={{p}^{2}}c\] done clear
  C)
             \[{{E}^{2}}=p{{c}^{2}}\]    done clear
  D)
             \[{{E}^{2}}={{p}^{2}}/{{c}^{2}}\] done clear
  View Solution play_arrow

• question_answer148)
  The work function for metals A, B and C are respectively 1.92 eV, 2.0 eV and 5 eV. According to Einstein?s equation, the metals which will emit photo electrons for a radiation of wavelength 4100 Å is/are           [CBSE PMT 2005]
  A)
             None of these                      done clear
  B)
             A only done clear
  C)
             A and B only                          done clear
  D)
             All the three metals done clear
  View Solution play_arrow

• question_answer149)
  A photosensitive metallic surface has work function \[h{{v}_{0}}\]. If photons of energy \[2h{{v}_{0}}\] fall on this surface the electrons come out with a maximum velocity of \[4\times {{10}^{6}}\,m/s\]. When the photon energy is increases to \[5h{{v}_{0}}\] then maximum velocity of photo electron will be      [CBSE PMT 2005]
  A)
             \[2\times {{10}^{6}}\,m/s\]    done clear
  B)
             \[2\times {{10}^{7}}\,m/s\] done clear
  C)
             \[8\times {{10}^{5}}\,m/s\]    done clear
  D)
             \[8\times {{10}^{6}}\,m/s\] done clear
  View Solution play_arrow

• question_answer150)
  A photocell is illuminated by a small bright source placed 1 m away. When the same source of light is placed \[\frac{1}{2}m\] away, the number of electrons emitted by photo cathode would            [CBSE PMT 2001; AIEEE 2005]
  A)
             Decrease by a factor of 2 done clear
  B)
             Increase by a factor of 2 done clear
  C)
             Decrease by a factor of 4 done clear
  D)
             Increase by a factor of 4 done clear
  View Solution play_arrow

• question_answer151)
  The magnitude of saturation photoelectric current depends upon            [AFMC 2005]
  A)
             Frequency                             done clear
  B)
             Intensity done clear
  C)
             Work function                      done clear
  D)
             Stopping potential done clear
  View Solution play_arrow

• question_answer152)
  For photoelectric emission, tungsten requires light of 2300 Å. If light of 1800 Å wavelength is incident then emission [AFMC 2005]
  A)
             Takes place done clear
  B)
             Don?t take place done clear
  C)
             May or may not take place done clear
  D)
             Depends on frequency done clear
  View Solution play_arrow

• question_answer153)
  The light rays having photons of energy 1.8 eV are falling on a metal surface having a work function 1.2 eV. What is the stopping potential to be applied to stop the emitting electrons                                  [BHU 2005]
  A)
             3 eV                                          done clear
  B)
             1.2 eV done clear
  C)
             0.6 eV                                      done clear
  D)
             1.4 eV done clear
  View Solution play_arrow

• question_answer154)
  The incident photon involved in the photoelectric effect experiment.                                    [EAMCET 2005]
  A)
             Completely disappears     done clear
  B)
             Comes out with an increased frequency                                                                    done clear
  C)
             Comes out with a decreased frequency done clear
  D)
             Comes out without change in frequency done clear
  View Solution play_arrow

• question_answer155)
  A photon of energy 8 eV is incident on metal surface of threshold frequency \[1.6\times {{10}^{15}}Hz.\] The maximum kinetic energy of the photoelectrons emitted (in eV) (Take \[h=6\times {{10}^{-34}}Js)\].                                             [MP. PET  2005]
  A)
             1.6  done clear
  B)
             6 done clear
  C)
             2     done clear
  D)
             1.2 done clear
  View Solution play_arrow