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MCQOPTIONS
This section includes 12583 Mcqs, each offering curated multiple-choice questions to sharpen your Joint Entrance Exam - Main (JEE Main) knowledge and support exam preparation. Choose a topic below to get started.
| 4051. |
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 |
| B. | 0.6 V |
| C. | 1.2 V |
| D. | 2.4 V |
| Answer» C. 1.2 V | |
| 4052. |
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 |
| B. | 6.2 eV |
| C. | 100 eV |
| D. | 200 eV |
| Answer» C. 100 eV | |
| 4053. |
Stopping potential for photoelectrons [MP PET 1994] |
| A. | Does not depend on the frequency of the incident light |
| B. | Does not depend upon the nature of the cathode material |
| C. | Depends on both the frequency of the incident light and nature of the cathode material |
| D. | Depends upon the intensity of the incident light |
| Answer» D. Depends upon the intensity of the incident light | |
| 4054. |
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. | \[2.1\times {{10}^{-19}}J\] |
| B. | \[8.5\times {{10}^{-19}}J\] |
| C. | \[5.3\times {{10}^{-19}}J\] |
| D. | \[3.2\times {{10}^{-19}}J\] \[(h=6.63\times {{10}^{-34}}Js)\] |
| Answer» B. \[8.5\times {{10}^{-19}}J\] | |
| 4055. |
The momentum of a photon of energy \[h\nu \]will be [DCE 2000] |
| A. | \[h\nu \] |
| B. | \[h\nu /c\] |
| C. | \[h\nu c\] |
| D. | \[h/\nu \] |
| Answer» C. \[h\nu c\] | |
| 4056. |
Photo cell is a device to [MP PET 1993] |
| A. | Store photons |
| B. | Measure light intensity |
| C. | Convert photon energy into mechanical energy |
| D. | Store electrical energy for replacing storage batteries |
| Answer» C. Convert photon energy into mechanical energy | |
| 4057. |
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 |
| B. | 2.29 eV |
| C. | 1.14 eV |
| D. | 0.57 eV |
| Answer» C. 1.14 eV | |
| 4058. |
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 |
| B. | Less than 2 V |
| C. | Zero |
| D. | Greater than 2 V |
| Answer» E. | |
| 4059. |
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 |
| B. | Moves with one-fourth of momentum as that of the initial momentum |
| C. | Will be half in number |
| D. | Will be one-fourth in number |
| Answer» E. | |
| 4060. |
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. | \[1.72\times {{10}^{31}}\] |
| B. | \[1327\times {{10}^{34}}\] |
| C. | \[13.27\times {{10}^{34}}\] |
| D. | \[0.075\times {{10}^{-34}}\] |
| Answer» B. \[1327\times {{10}^{34}}\] | |
| 4061. |
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. | \[6.62\times {{10}^{-48}}\] |
| B. | \[6.62\times {{10}^{-20}}\] |
| C. | \[\frac{6.62}{3}\times {{10}^{-28}}\] |
| D. | \[3\times 6.62\times {{10}^{-28}}\] |
| Answer» C. \[\frac{6.62}{3}\times {{10}^{-28}}\] | |
| 4062. |
Photoelectric effect was successfully explained first by |
| A. | Planck |
| B. | Hallwash |
| C. | Hertz |
| D. | Einstein |
| Answer» E. | |
| 4063. |
The photoelectric threshold wavelength for a metal surface is 6600 Å. The work function for this is [MP PET 1991] |
| A. | 1.87 V |
| B. | 1.87 eV |
| C. | 18.7 eV |
| D. | 0.18 eV |
| Answer» C. 18.7 eV | |
| 4064. |
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 |
| B. | 2.24 volts |
| C. | 3.6 volts |
| D. | 4.8 volts |
| Answer» B. 2.24 volts | |
| 4065. |
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 |
| B. | 1.7 eV |
| C. | 5.4 eV |
| D. | 6.8 eV |
| Answer» B. 1.7 eV | |
| 4066. |
The momentum of the photon of wavelength 5000Å will be [CPMT 1987] |
| A. | \[1.3\times {{10}^{-27}}kg\text{-}\]m/sec |
| B. | \[1.3\times {{10}^{-28}}kg\text{-}\]m/sec |
| C. | \[4\times {{10}^{29}}kg\text{-}\]m/sec |
| D. | \[4\times {{10}^{-18}}kg\text{-}\]m/sec |
| Answer» B. \[1.3\times {{10}^{-28}}kg\text{-}\]m/sec | |
| 4067. |
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 |
| B. | 10683 Å |
| C. | 2791 Å |
| D. | 528 Å |
| Answer» D. 528 Å | |
| 4068. |
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. | \[3.2\times {{10}^{-21}}\] |
| B. | \[3.2\times {{10}^{-19}}\] |
| C. | \[3.2\times {{10}^{-17}}\] |
| D. | \[3.2\times {{10}^{-15}}\] |
| Answer» C. \[3.2\times {{10}^{-17}}\] | |
| 4069. |
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. | \[14\times {{10}^{-19}}\ J\] |
| B. | \[2.8\times {{10}^{-19}}\ J\] |
| C. | \[1.4\times {{10}^{-19}}J\] |
| D. | \[1.4\times {{10}^{-19}}\,eV\] |
| Answer» D. \[1.4\times {{10}^{-19}}\,eV\] | |
| 4070. |
The retarding potential for having zero photo-electron current [MP PMT/PET 1988] |
| A. | Is proportional to the wavelength of incident light |
| B. | Increases uniformly with the increase in the wavelength of incident light |
| C. | Is proportional to the frequency of incident light |
| D. | Increases uniformly with the increase in the frequency of incident light wave |
| Answer» E. | |
| 4071. |
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 |
| B. | \[1\times {{10}^{3}}\]m/sec |
| C. | \[1\times {{10}^{4}}m/\sec \]m/sec |
| D. | \[1\times {{10}^{6}}m/\sec \]m/sec |
| Answer» E. | |
| 4072. |
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 |
| B. | The frequency of incident light increases |
| C. | The wavelength of the incident light increases |
| D. | The intensity of the incident light increases |
| Answer» E. | |
| 4073. |
The work function of a metal is 4.2 eV, its threshold wavelength will be [BHU 2003; CPMT 2004] |
| A. | 4000 Å |
| B. | 3500 Å |
| C. | 2955 Å |
| D. | 2500 Å |
| Answer» D. 2500 Å | |
| 4074. |
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 |
| B. | Only if the temperature of the surface is high |
| C. | At a rate that is independent of the nature of the metal |
| D. | With a maximum velocity proportional to the frequency of the incident radiation |
| Answer» B. Only if the temperature of the surface is high | |
| 4075. |
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 |
| B. | Frequency of the incident light |
| C. | Intensity of the incident light |
| D. | Velocity of the incident light |
| Answer» C. Intensity of the incident light | |
| 4076. |
The rest mass of the photon is [MP PET 1994; CPMT 1996; RPMT 1999; JIPMER 2002] |
| A. | 0 |
| B. | \[\infty \] |
| C. | Between 0 and \[\infty \] |
| D. | Equal to that of an electron |
| Answer» B. \[\infty \] | |
| 4077. |
In a photo cell, the photo-electrons emission takes place |
| A. | After \[{{10}^{1}}\] sec on incident of light rays |
| B. | After \[{{10}^{3}}\]sec on incident of light rays |
| C. | After \[{{10}^{6}}\]sec on incident of light rays |
| D. | After \[{{10}^{8}}\]sec on incident of light rays |
| Answer» E. | |
| 4078. |
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 |
| B. | 3.74 eV |
| C. | 2.66 eV |
| D. | 1.07 eV |
| Answer» D. 1.07 eV | |
| 4079. |
The photo-electrons emitted from a surface of sodium metal are such that [MP PMT 1992] |
| A. | They all are of the same frequency |
| B. | They have the same kinetic energy |
| C. | They have the same de Broglie wavelength |
| D. | They have their speeds varying from zero to a certain maximum |
| Answer» E. | |
| 4080. |
Einstein got Nobel prize on which of the following works [DCE 1995] |
| A. | Mass-energy relation |
| B. | Special theory of relativity |
| C. | Photoelectric equation |
| D. | (a) and (b) both |
| Answer» D. (a) and (b) both | |
| 4081. |
Photo cells are used for the |
| A. | Reproduction of pictures from the cinema film |
| B. | Reproduction of sound from the cinema film |
| C. | Automatic switching of street light |
| D. | (b) and (c) both |
| Answer» E. | |
| 4082. |
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 |
| B. | Photo-electrons come out with zero speed |
| C. | Photo-electrons come out with 103 m/sec speed |
| D. | Photo-electrons come out with 105 m/sec speed |
| Answer» B. Photo-electrons come out with zero speed | |
| 4083. |
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 |
| B. | 1 watt infrared lamp |
| C. | 50 watt ultraviolet lamp |
| D. | 1 watt ultraviolet lamp |
| E. | (e) Both (c) and (d) |
| Answer» F. | |
| 4084. |
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 |
| B. | Independent of the frequency of light |
| C. | Inversely proportional to the intensity of illumination |
| D. | Directly proportional to the intensity of illumination |
| Answer» B. Independent of the frequency of light | |
| 4085. |
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 |
| B. | Mean kinetic energy of the emitted electrons |
| C. | Maximum kinetic energy of the emitted electrons |
| D. | Minimum kinetic energy of the emitted electrons |
| Answer» D. Minimum kinetic energy of the emitted electrons | |
| 4086. |
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. | \[\frac{{{n}_{1}}}{{{n}_{2}}}=1\] |
| B. | \[\frac{{{n}_{1}}}{{{n}_{2}}}=\frac{{{\gamma }_{1}}}{{{\gamma }_{2}}}\] |
| C. | \[\frac{{{n}_{1}}}{{{n}_{2}}}=\frac{{{\gamma }_{2}}}{{{\gamma }_{1}}}\] |
| D. | \[\frac{{{n}_{1}}}{{{n}_{2}}}=\frac{\gamma _{1}^{2}}{\gamma _{2}^{2}}\] |
| Answer» D. \[\frac{{{n}_{1}}}{{{n}_{2}}}=\frac{\gamma _{1}^{2}}{\gamma _{2}^{2}}\] | |
| 4087. |
The momentum of a photon is\[2\times {{10}^{-16}}\]gm-cm/sec. Its energy is [CPMT 1974] |
| A. | \[0.61\times {{10}^{-26}}erg\] |
| B. | \[2.0\times {{10}^{-26}}erg\] |
| C. | \[6\times {{10}^{-6}}erg\] |
| D. | \[6\times {{10}^{-8}}erg\] |
| Answer» D. \[6\times {{10}^{-8}}erg\] | |
| 4088. |
Energy of photon whose frequency is \[{{10}^{12}}MHz,\] will be [MH CET 2002] |
| A. | \[4.14\times {{10}^{3}}keV\] |
| B. | \[4.14\times {{10}^{2}}eV\] |
| C. | \[4.14\times {{10}^{3}}MeV\] |
| D. | \[4.14\times {{10}^{3}}eV\] |
| Answer» E. | |
| 4089. |
The mass of a photo electron is [MP PMT 2002] |
| A. | \[9.1\times {{10}^{-27}}\,kg\] |
| B. | \[9.1\times {{10}^{-29}}\,kg\] |
| C. | \[9.1\times {{10}^{-31}}\,kg\] |
| D. | \[9.1\times {{10}^{-34}}\,kg\] |
| Answer» D. \[9.1\times {{10}^{-34}}\,kg\] | |
| 4090. |
If a photon has velocity c and frequency n, then which of following represents its wavelength [AIEEE 2002] |
| A. | \[\frac{hc}{E}\] |
| B. | \[\frac{h\nu }{c}\] |
| C. | \[\frac{h\nu }{{{c}^{2}}}\] |
| D. | \[h\nu \] |
| Answer» B. \[\frac{h\nu }{c}\] | |
| 4091. |
Which of the following is incorrect statement regarding photon [MH CET (Med.) 2001] |
| A. | Photon exerts no pressure |
| B. | Photon energy is \[hv\] |
| C. | Photon rest mass is zero |
| D. | None of these |
| Answer» B. Photon energy is \[hv\] | |
| 4092. |
Which of the following is true for photon [RPET 2001] |
| A. | \[E=\frac{hc}{\lambda }\] |
| B. | \[E=\frac{1}{2}m{{u}^{2}}\] |
| C. | \[p=\frac{E}{2v}\] |
| D. | \[E=\frac{1}{2}m{{c}^{2}}\] |
| Answer» B. \[E=\frac{1}{2}m{{u}^{2}}\] | |
| 4093. |
A photon of wavelength 4400 Å is passing through vacuum. The effective mass and momentum of the photon are respectively [AMU 2000] |
| A. | \[5\times {{10}^{-36}}kg,\,\,1.5\times {{10}^{-27}}\,kg\text{-}m/s\] |
| B. | \[5\times {{10}^{-35}}kg,\,\,1.5\times {{10}^{-26}}\,kg\text{-}m/s\] |
| C. | Zero, \[1.5\times {{10}^{-26}}\,kg\text{-}m/s\] |
| D. | \[5\times {{10}^{-36}}kg,\,1.67\times {{10}^{-43}}kg\text{-}m/s\] |
| Answer» B. \[5\times {{10}^{-35}}kg,\,\,1.5\times {{10}^{-26}}\,kg\text{-}m/s\] | |
| 4094. |
The frequency of a photon, having energy 100 \[eV\] is\[(h=6.6\,{{10}^{-34}}\,J\text{-}sec)\] [AFMC 2000] |
| A. | \[2.42\times {{10}^{26}}Hz\] |
| B. | \[2.42\times {{10}^{16}}Hz\] |
| C. | \[2.42\times {{10}^{12}}Hz\] |
| D. | \[2.42\times {{10}^{9}}Hz\] |
| Answer» C. \[2.42\times {{10}^{12}}Hz\] | |
| 4095. |
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. | \[E=12.4\,h\nu \] |
| B. | \[E=12.4\,h/\lambda \] |
| C. | \[E=12.4\,/\lambda \] |
| D. | \[E=h\nu \] |
| Answer» D. \[E=h\nu \] | |
| 4096. |
Which of the following statement is not correct [AFMC 1999] |
| A. | Photographic plates are sensitive to infrared rays |
| B. | Photographic plates are sensitive to ultraviolet rays |
| C. | Infra-red rays are invisible but can cast shadows like visible light |
| D. | Infrared photons have more energy than photons of visible light |
| Answer» E. | |
| 4097. |
The energy of a photon of wavelength \[\lambda \]is given by [CPMT 1974; CBSE PMT 1992; DCE 1998; BHU 2000; DPMT 2001] |
| A. | \[h\lambda \] |
| B. | \[ch\lambda \] |
| C. | \[\lambda /hc\] |
| D. | \[hc/\lambda \] |
| Answer» E. | |
| 4098. |
The energy of a photon of light of wavelength 450 nm is [BHU 1997; JIPMER 2000] |
| A. | \[4.4\times {{10}^{-19}}J\] |
| B. | \[2.5\times {{10}^{-19}}J\] |
| C. | \[1.25\times {{10}^{-17}}J\] |
| D. | \[2.5\times {{10}^{-17}}J\] |
| Answer» B. \[2.5\times {{10}^{-19}}J\] | |
| 4099. |
What is the momentum of a photon having frequency \[1.5\times {{10}^{13}}Hz\] [BHU 1997] |
| A. | \[3.3\times {{10}^{-29}}kg\ m/s\] |
| B. | \[3.3\times {{10}^{-34}}kg\ m/s\] |
| C. | \[6.6\times {{10}^{-34}}kg\ m/s\] |
| D. | \[6.6\times {{10}^{-30}}kg\ m/s\] |
| Answer» B. \[3.3\times {{10}^{-34}}kg\ m/s\] | |
| 4100. |
Momentum of a photon of wavelength l is [CBSE PMT 1993; JIPMER 2001, 02] |
| A. | \[\frac{h}{\lambda }\] |
| B. | Zero |
| C. | \[\frac{h\lambda }{{{c}^{2}}}\] |
| D. | \[\frac{h\lambda }{c}\] |
| Answer» B. Zero | |