MCQOPTIONS
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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.
| 4001. |
What should be the angle between two plane mirrors so that whatever be the angle of incidence, the incident ray and the reflected ray from the two mirrors be parallel to each other [KCET 1994; SCRA 1994] |
| A. | \[60{}^\circ \] |
| B. | \[90{}^\circ \] |
| C. | \[120{}^\circ \] |
| D. | \[175{}^\circ \] |
| Answer» C. \[120{}^\circ \] | |
| 4002. |
A watch shows time as \[3:25\] when seen through a mirror, time appeared will be [RPMT 1997; JIPMER 2001, 02] |
| A. | \[8:35\] |
| B. | \[9:35\] |
| C. | \[7:35\] |
| D. | \[8:25\] |
| Answer» B. \[9:35\] | |
| 4003. |
A plane mirror makes an angle of \[30{}^\circ \] with horizontal. If a vertical ray strikes the mirror, find the angle between mirror and reflected ray [RPET 1997] |
| A. | \[30{}^\circ \] |
| B. | \[45{}^\circ \] |
| C. | \[60{}^\circ \] |
| D. | \[90{}^\circ \] |
| Answer» D. \[90{}^\circ \] | |
| 4004. |
A plane mirror produces a magnification of [MP PET/PMT 1997] |
| A. | \[-1\] |
| B. | \[+1\] |
| C. | Zero |
| D. | Between 0 and \[+\,\,\infty \] |
| Answer» C. Zero | |
| 4005. |
When a plane mirror is rotated through an angle \[\theta \]then the reflected ray turns through the angle \[2\theta \] then the size of the image |
| A. | Is doubled |
| B. | Is halved |
| C. | Remains the same |
| D. | Becomes infinite |
| Answer» D. Becomes infinite | |
| 4006. |
Two plane mirrors are at right angles to each other. A man stands between them and combs his hair with his right hand. In how many of the images will he be seen using his right hand [MP PMT 1995; UPSEAT 2001] |
| A. | None |
| B. | 1 |
| C. | 2 |
| D. | 3 |
| Answer» C. 2 | |
| 4007. |
A ray is reflected in turn by three plain mirrors mutually at right angles to each other. The angle between the incident and the reflected rays is [Roorkee 1995] |
| A. | \[90{}^\circ \] |
| B. | \[60{}^\circ \] |
| C. | \[180{}^\circ \] |
| D. | None of these |
| Answer» D. None of these | |
| 4008. |
When light wave suffers reflection at the interface from air to glass, the change in phase of the reflected wave is equal to [CPMT 1991; J & KCET 2004] |
| A. | 0 |
| B. | \[\frac{\pi }{2}\] |
| C. | \[\pi \] |
| D. | \[2\pi \] |
| Answer» D. \[2\pi \] | |
| 4009. |
A ray of light is incidenting normally on a plane mirror. The angle of reflection will be [MP PET 2000] |
| A. | \[0{}^\circ \] |
| B. | \[90{}^\circ \] |
| C. | Will not be reflected |
| D. | None of the above |
| Answer» B. \[90{}^\circ \] | |
| 4010. |
A ray of light incidents on a plane mirror at an angle of \[30{}^\circ .\] The deviation produced in the ray is |
| A. | \[30{}^\circ \] |
| B. | \[60{}^\circ \] |
| C. | \[90{}^\circ \] |
| D. | \[120{}^\circ \] |
| Answer» E. | |
| 4011. |
A person is in a room whose ceiling and two adjacent walls are mirrors. How many images are formed [AFMC 2002] |
| A. | 5 |
| B. | 6 |
| C. | 7 |
| D. | 8 |
| Answer» D. 8 | |
| 4012. |
When a plane mirror is placed horizontally on a level ground at a distance of \[60m\] from the foot of a tower, the top of the tower and its image in the mirror subtend an angle of \[90{}^\circ \] at the eye. The height of the tower will be [CPMT 1984] |
| A. | \[30m\] |
| B. | \[60m\] |
| C. | \[90m\] |
| D. | \[120m\] |
| Answer» C. \[90m\] | |
| 4013. |
A man is \[180cm\] tall and his eyes are \[10cm\] below the top of his head. In order to see his entire height right from toe to head, he uses a plane mirror kept at a distance of \[1m\] from him. The minimum length of the plane mirror required is [MP PMT 1993; DPMT 2001] |
| A. | \[180cm\] |
| B. | \[90cm\] |
| C. | \[85cm\] |
| D. | \[170cm\] |
| Answer» C. \[85cm\] | |
| 4014. |
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. | \[3\times {{10}^{5}}\] |
| B. | \[{{K}_{A}}={{K}_{B}}/2\] |
| C. | \[4\times {{10}^{4}}\] |
| D. | \[3.65\times {{10}^{7}}\] |
| Answer» C. \[4\times {{10}^{4}}\] | |
| 4015. |
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. | \[8.4\times {{10}^{5}}m/sec\] |
| B. | \[7.4\times {{10}^{5}}m/sec\] |
| C. | \[6.4\times {{10}^{5}}m/sec\] |
| D. | \[8.4\times {{10}^{6}}m/sec\] |
| Answer» B. \[7.4\times {{10}^{5}}m/sec\] | |
| 4016. |
In photoelectric effect if the intensity of light is doubled then maximum kinetic energy of photoelectrons will become [RPMT 1999] |
| A. | Double |
| B. | Half |
| C. | Four time |
| D. | No change |
| Answer» E. | |
| 4017. |
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 |
| B. | Not possible |
| C. | Data is incomplete |
| D. | Depend upon the density of the surface |
| Answer» C. Data is incomplete | |
| 4018. |
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 |
| B. | 1.36 eV |
| C. | 1.10 eV |
| D. | 0.43 eV |
| Answer» D. 0.43 eV | |
| 4019. |
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 |
| B. | Sodium |
| C. | Both |
| D. | Neither of them |
| Answer» C. Both | |
| 4020. |
A photocell stops emission if it is maintained at 2V negative potential. The energy of most energetic photoelectron is [JIPMER 1999] |
| A. | 2eV |
| B. | 2J |
| C. | 2kJ |
| D. | 2keV |
| Answer» B. 2J | |
| 4021. |
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 |
| B. | Photons are emitted |
| C. | Electrons of higher energy are emitted |
| D. | Electrons of lower energy are emitted |
| Answer» B. Photons are emitted | |
| 4022. |
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 |
| B. | 3.6 V |
| C. | 0.8 V |
| D. | 1.4 V |
| Answer» E. | |
| 4023. |
Which of the following statements is correct [CBSE PMT 1997] |
| A. | The current in a photocell increases with increasing frequency of light |
| B. | The photocurrent is proportional to applied voltage |
| C. | The photocurrent increases with increasing intensity of light |
| D. | The stopping potential increases with increasing intensity of incident light |
| Answer» D. The stopping potential increases with increasing intensity of incident light | |
| 4024. |
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 \[E\propto L\] |
| B. | \[N\propto L\]and \[E\propto \frac{1}{\lambda }\] |
| C. | \[N\propto \lambda \] and \[E\propto L\] |
| D. | \[N\propto \frac{1}{\lambda }\]and \[E\propto \frac{1}{L}\] |
| Answer» C. \[N\propto \lambda \] and \[E\propto L\] | |
| 4025. |
Threshold wavelength for photoelectric effect on sodium is 5000 Å. Its work function is [CBSE PMT 1993] |
| A. | 15 J |
| B. | \[16\times {{10}^{-14}}J\] |
| C. | \[4\times {{10}^{-19}}J\] |
| D. | \[4\times {{10}^{-81}}J\] |
| Answer» D. \[4\times {{10}^{-81}}J\] | |
| 4026. |
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. | \[{{I}_{1}}={{I}_{2}}\] |
| B. | \[{{I}_{1}}<{{I}_{2}}\] |
| C. | \[{{I}_{1}}>{{I}_{2}}\] |
| D. | \[{{I}_{1}}<{{I}_{2}}<2{{I}_{1}}\] |
| Answer» B. \[{{I}_{1}}<{{I}_{2}}\] | |
| 4027. |
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 |
| B. | 2 : 1 |
| C. | 4 : 1 |
| D. | 1 : 4 |
| Answer» C. 4 : 1 | |
| 4028. |
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 |
| B. | Unchanged |
| C. | More than doubled |
| D. | Less than doubled |
| Answer» D. Less than doubled | |
| 4029. |
If mean wavelength of light radiated by 100 W lamp is 5000 Å, then number of photons radiated per second are [RPET 1997] |
| A. | \[3\times {{10}^{23}}\] |
| B. | \[2.5\times {{10}^{22}}\] |
| C. | \[2.5\times {{10}^{20}}\] |
| D. | \[5\times {{10}^{17}}\] |
| Answer» D. \[5\times {{10}^{17}}\] | |
| 4030. |
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 |
| B. | 4 |
| C. | 6 |
| D. | 10 |
| Answer» C. 6 | |
| 4031. |
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 |
| B. | 5500 Å, 6000 Å |
| C. | 4000 Å, 6000 Å |
| D. | None of these |
| Answer» E. | |
| 4032. |
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 |
| B. | 400 nm |
| C. | 310 nm |
| D. | 220 nm |
| Answer» D. 220 nm | |
| 4033. |
If the momentum of a photon is p, then its frequency is [MP PET 1989] |
| A. | \[\frac{ph}{c}\] |
| B. | \[\frac{pc}{h}\] |
| C. | \[\frac{mh}{c}\] |
| D. | \[\frac{mc}{h}\] Where m is the rest mass of the photon |
| Answer» C. \[\frac{mh}{c}\] | |
| 4034. |
Which of the following is dependent on the intensity of incident radiation in a photoelectric experiment [AIIMS 1998] |
| A. | Work function of the surface |
| B. | Amount of photoelectric current |
| C. | Stopping potential will be reduced |
| D. | Maximum kinetic energy of photoelectrons |
| Answer» C. Stopping potential will be reduced | |
| 4035. |
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 |
| B. | 2.48 eV |
| C. | 1.24 eV |
| D. | 1.16 eV |
| Answer» B. 2.48 eV | |
| 4036. |
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 |
| B. | Photoelectric current decreases |
| C. | Kinetic energy of emitted photoelectrons increases |
| D. | Kinetic energy of emitted photoelectrons decreases |
| Answer» B. Photoelectric current decreases | |
| 4037. |
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 |
| B. | 2062.5 Å |
| C. | 3000 Å |
| D. | 6000 Å |
| Answer» D. 6000 Å | |
| 4038. |
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 |
| B. | Stopping potential will increase |
| C. | Kinetic energy of emitted electrons will decrease |
| D. | The value of work function will decrease |
| Answer» C. Kinetic energy of emitted electrons will decrease | |
| 4039. |
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. | \[\lambda '=\frac{\lambda }{2}\] |
| B. | \[\lambda '=2\lambda \] |
| C. | \[\frac{\lambda }{2}<\lambda '<\lambda \] |
| D. | \[\lambda '>\lambda \] |
| Answer» D. \[\lambda '>\lambda \] | |
| 4040. |
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 |
| B. | Each emitted electron carries half the initial energy |
| C. | Number of electrons emitted is a quarter of the initial number |
| D. | Each emitted electron carries one quarter of the initial energy |
| Answer» D. Each emitted electron carries one quarter of the initial energy | |
| 4041. |
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. | \[\nu <\frac{\varphi }{h}\] |
| B. | \[\nu =\frac{\varphi }{h}\] |
| C. | \[\nu >\frac{\varphi }{h}\] |
| D. | \[\nu >\ =\ <\frac{\varphi }{h}\] |
| Answer» B. \[\nu =\frac{\varphi }{h}\] | |
| 4042. |
The work function of a photoelectric material is 3.3 eV. The threshold frequency will be equal to [UPSEAT 1999] |
| A. | \[8\times {{10}^{4}}Hz\] |
| B. | \[8\times {{10}^{56}}Hz\] |
| C. | \[8\times {{10}^{10}}Hz\] |
| D. | \[8\times {{10}^{14}}Hz\] |
| Answer» E. | |
| 4043. |
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 |
| B. | V/2 |
| C. | V/4 |
| D. | \[V/\sqrt{2}\] |
| Answer» B. V/2 | |
| 4044. |
A photon in motion has a mass [MP PMT 1992] |
| A. | \[c/h\nu \] |
| B. | \[h/\nu \] |
| C. | \[h\nu \] |
| D. | \[h\nu /{{c}^{2}}\] |
| Answer» E. | |
| 4045. |
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 |
| B. | Photoelectric current is directly proportional to the intensity of light of a given frequency at moderate intensities |
| C. | Above the threshold frequency, the maximum K.E. of photoelectrons is inversely proportional to the frequency of incident light |
| D. | The threshold frequency depends upon the wavelength of incident light |
| Answer» C. Above the threshold frequency, the maximum K.E. of photoelectrons is inversely proportional to the frequency of incident light | |
| 4046. |
Energy conversion in a photoelectric cell takes place from [AFMC 1993; MP PET 1996; MP PMT 1996] |
| A. | Chemical to electrical |
| B. | Magnetic to electrical |
| C. | Optical to electrical |
| D. | Mechanical to electrical |
| Answer» D. Mechanical to electrical | |
| 4047. |
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 |
| B. | \[6.5\times {{10}^{14}}cycle/\sec \]cycle/sec |
| C. | \[9.4\times {{10}^{14}}cycle/\sec \]cycle/sec |
| D. | \[6.08\times {{10}^{14}}\] cycle/sec |
| Answer» E. | |
| 4048. |
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 |
| B. | \[\frac{1}{4}\] |
| C. | 2 |
| D. | \[\frac{1}{2}\] |
| Answer» E. | |
| 4049. |
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 |
| B. | 2.0 |
| C. | 2.2 |
| D. | 3.1 |
| Answer» B. 2.0 | |
| 4050. |
The minimum energy required to remove an electron is called [AFMC 1995; DPMT 2001] |
| A. | Stopping potential |
| B. | Kinetic energy |
| C. | Work function |
| D. | None of these |
| Answer» D. None of these | |