JEE Main
Physics
Previous Years Questions

This equation has Statement 1 and Statement 2. Of the four choices given after the statements, choose the one that describes the two statements. State...
The threshold frequency of a metal is $$f_{0}$$. When the light of frequency $$2 f_{0}$$ is incident on the metal plate, the maximum velocity of photo...
If the two metals $\mathrm{A}$ and $\mathrm{B}$ are exposed to radiation of wavelength $350 \mathrm{~nm}$. The work functions of metals $\mathrm{A}$ a...
Given below are two statements : One is labelled as Assertion A and the other is labelled as Reason R Assertion A : The beam of electrons show wave na...
If a source of electromagnetic radiation having power $$15 \mathrm{~kW}$$ produces $$10^{16}$$ photons per second, the radiation belongs to a part of ...
An electron accelerated through a potential difference $V_{1}$ has a de-Broglie wavelength of $\lambda$. When the potential is changed to $V_{2}$, its...
A small object at rest, absorbs a light pulse of power $$20 \mathrm{~mW}$$ and duration $$300 \mathrm{~ns}$$. Assuming speed of light as $$3 \times 10... The threshold wavelength for photoelectric emission from a material is 5500$$\mathop A\limits^o $$. Photoelectrons will be emitted, when this materia... Given below are two statements : Statement I : Stopping potential in photoelectric effect does not depend on the power of the light source. Statement ... Electron beam used in an electron microscope, when accelerated by a voltage of 20 kV, has a de-Broglie wavelength of$$\lambda_0$$. IF the voltage is ... A photon is emitted in transition from n = 4 to n = 1 level in hydrogen atom. The corresponding wavelength for this transition is (given, h = 4$$\tim...
From the photoelectric effect experiment, following observations are made. Identify which of these are correct. A. The stopping potential depends only...
The kinetic energy of emitted electron is E when the light incident on the metal has wavelength $$\lambda$$. To double the kinetic energy, the inciden...
Two streams of photons, possessing energies equal to five and ten times the work function of metal are incident on the metal surface successively. The...
The half life period of a radioactive substance is 60 days. The time taken for $$\frac{7}{8}$$th of its original mass to disintegrate will be :
With reference to the observations in photo-electric effect, identify the correct statements from below : (A) The square of maximum velocity of photoe...
A metal exposed to light of wavelength $$800 \mathrm{~nm}$$ and and emits photoelectrons with a certain kinetic energy. The maximum kinetic energy of ...
A source of monochromatic light liberates 9 $$\times$$ 1020 photon per second with wavelength 600 nm when operated at 400 W. The number of photons emi...
The electric field at a point associated with a light wave is given by E = 200 [sin (6 $$\times$$ 1015)t + sin (9 $$\times$$ 1015)t] Vm$$-$$1 Given : ...
Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R : Assertion A : The photoelectric effect does no...
The Q-value of a nuclear reaction and kinetic energy of the projectile particle, Kp are related as :
Given below are two statements : Statement I : In hydrogen atom, the frequency of radiation emitted when an electron jumps from lower energy orbit (E1...
How many alpha and beta particles are emitted when Uranium 92U238 decays to lead 82Pb206 ?
Given below are two statements : Statement I : Davisson-Germer experiment establishes the wave nature of electrons. Statement II : If electrons have w...
The light of two different frequencies whose photons have energies 3.8 eV and 1.4 eV respectively, illuminate a metallic surface whose work function i...
Nucleus A is having mass number 220 and its binding energy per nucleon is 5.6 MeV. It splits in two fragments 'B' and 'C' of mass numbers 105 and 115....
The temperature of an ideal gas in 3-dimensions is 300 K. The corresponding de-Broglie wavelength of the electron approximately at 300 K, is :[me = ma...
The half life period of radioactive element x is same as the mean life time of another radioactive element y. Initially they have the same number of a...
A free electron of 2.6 eV energy collides with a H+ ion. This results in the formation of a hydrogen atom in the first excited state and a photon is r...
Consider two separate ideal gases of electrons and protons having same number of particles. The temperature of both the gases are same. The ratio of t...
A monochromatic neon lamp with wavelength of 670.5 nm illuminates a photo-sensitive material which has a stopping voltage of 0.48 V. What will be the ...
In a photoelectric experiment, increasing the intensity of incident light :
The de-Broglie wavelength of a particle having kinetic energy E is $$\lambda$$. How much extra energy must be given to this particle so that the de-Br...
In a photoelectric experiment ultraviolet light of wavelength 280 nm is used with lithium cathode having work function $$\phi$$ = 2.5 eV. If the wavel...
If 'f' denotes the ratio of the number of nuclei decayed (Nd) to the number of nuclei at t = 0 (N0) then for a collection of radioactive nuclei, the r...
When radiation of wavelength $$\lambda$$ is incident on a metallic surface, the stopping potential of ejected photoelectrons is 4.8 V. If the same sur...
Some nuclei of a radioactive material are undergoing radioactive decay. The time gap between the instances when a quarter of the nuclei have decayed a...
The half-life of $${}^{198}Au$$ is 3 days. If atomic weight of $${}^{198}Au$$ is 198 g/mol then the activity of 2 mg of $${}^{198}Au$$ is [in disinteg...
An electron having de-Broglie wavelength $$\lambda$$ is incident on a target in a X-ray tube. Cut-off wavelength of emitted X-ray is :
The radiation corresponding to 3 $$\to$$ 2 transition of a hydrogen atom falls on a gold surface to generate photoelectrons. The electrons are passed ...
Two identical photocathodes receive the light of frequencies f1 and f2 respectively. If the velocities of the photo-electrons coming out are v1 and v2...
The stopping potential in the context of photoelectric effect depends on the following property of incident electromagnetic radiation :
The recoil speed of a hydrogen atom after it emits a photon in going from n = 5 state to n = 1 state will be :
Given below are two statements : one is labeled as Assertion A and the other is labelled as Reason R.Assertion A : An electron microscope can achieve ...
The wavelength of the photon emitted by a hydrogen atom when an electron makes a transition from n = 2 to n = 1 state is :
The stopping potential for electrons emitted from a photosensitive surface illuminated by light of wavelength 491 nm is 0.710 V. When the incident wav...
An $$\alpha$$ particle and a proton are accelerated from rest by a potential difference of 200V. After this, their de Broglie wavelengths are $$\lambd... An X-ray tube is operated at 1.24 million volt. The shortest wavelength of the produced photon will be : Match List - I with List - II. List I List II (a) Source of microwave frequency (i) Radioactive decay of... According to Bohr atom model, in which of the following transitions will the frequency be maximum? Given below are two statements : Statement I : Two photons having equal linear momenta have equal wavelengths.Statement II : If the wavelength of phot... Assuming the nitrogen molecule is moving with r.m.s. velocity at 400 K, the de-Broglie wavelength of nitrogen molecule is close to : (Given : nitroge... An electron, a doubly ionized helium ion (He++) and a proton are having the same kinetic energy. The relation between their respective de-Broglie wave... You are given that Mass of$${}_3^7Li$$= 7.0160u, Mass of$${}_2^4He$$= 4.0026u and Mass of$${}_1^1H$$= 1.0079u. When 20 g of$${}_3^7Li$$is conv... The correct match between the entries in column I and column II are : .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;bor... Find the Binding energy per neucleon for$${}_{50}^{120}Sn$$. Mass of proton mp = 1.00783 U, mass of neutron mn = 1.00867 U and mass of tin nucleus ... In a photoelectric effect experiment, the graph of stopping potential V versus reciprocal of wavelength obtained is shown in the figure. As the intens... Particle A of mass mA =$${m \over 2}$$moving along the x-axis with velocity v0 collides elastically with another particle B at rest having mass mB =... Given figure shows few data points in a phot electric effect experiment for a certain metal. The minimum energy for ejection of electron from its surf... Two sources of light emit X-rays of wavelength 1 nm and visible light of wavelength 500 nm, respectively. Both the sources emit light of the same powe... When the wavelength of radiation falling on a metal is changed from 500 nm to 200 nm, the maximum kinetic energy of the photoelectrons becomes three t... A particle is moving 5 times as fast as an electron. The ratio of the de-Broglie wavelength of the particle to that of the electron is 1.878$$ \times...
The energy required to ionise a hydrogen like ion in its ground state is 9 Rydbergs. What is the wavelength of the radiation emitted when the electron...
An electron of mass m and magnitude of charge |e| initially at rest gets accelerated by a constant electric field E. The rate of change of de-Broglie ...
A particle moving with kinetic energy E has de Broglie wavelength $$\lambda$$. If energy $$\Delta$$E is added to its energy, the wavelength become $... Radiation, with wavelength 6561 $$\mathop A\limits^o$$ falls on a metal surface to produce photoelectrons. The electrons are made to enter a uniform ... The activity of a radioactive sample falls from 700 s–1 to 500 s–1 in 30 minutes. Its half life is close to: An electron (of mass m) and a photon have the same energy E in the range of a few eV. The ratio of the de-Broglie wavelength associated with the elect... Consider an electron in a hydrogen atom revolving in its second excited state (having radius 4.65 $$\mathop A\limits^o$$). The de-Broglie wavelength ... The stopping potential V0 (in volt) as a function of frequency ($$\upsilon$$) for a sodium emitter, is shown in the figure. The work function of sodi... A 2 mW laser operates at wavelength of 500 nm. The number of photons that will be emitted per second is : [Given Planck's constant h = 6.6 × 10–34 Js,... In a photoelectric effect experiment the threshold wavelength of the light is 380 nm. If the wavelentgh of incident light is 260 nm, the maximum kinet... A particle 'P' is formed due to a completely inelastic collision of particles 'x' and 'y' having de-Broglie wavelengths '$$\lambda$$x' and '$$\lambda... The electric field of light wave is given as$$$\overrightarrow E = {10^{ - 3}}\cos \left( {{{2\pi x} \over {5 \times {{10}^{ - 7}}}} - 2\pi \times ...
A nucleus A, with a finite de-broglie wavelength $$\lambda$$A, undergoes spontaneous fission into two nuclei B and C of equal mass. B flies in the sa...
Two particles move at right angle to each other. Their de-Broglie wavelengths are $$\lambda _1$$ and $$\lambda _2$$ respectively. The particles suffer...
In a Frank-Hertz experiment, an electron of energy 5.6 eV passes through mercury vapour and emerges with an energy 0.7 eV. The minimum wavelength of p...
When a certain photosensitive surface is illuminated with monochromatic light of frequency v, the stopping potential for the current is –V0/2. When th...
A particle A of mass 'm' and charge 'q' is accelerated by a potential difference of 50 V. Another particle B of mass ' 4 m' and charge 'q' is accelera...
In a photoelectric experiment, the wavelength of the light incident on a metal is changed from 300 nm to 400 nm. The decrease in the stopping potentia...
If the de Broglie wavelength of an electron is equal to the 10–3 times the wavelength of a photon of frequency 6 $$\times$$ 1014 Hz, then the spee...
A metal plate of area 1 $$\times$$ 10–4 m2 is illuminated by a radiation of intensity 16 mW/m2. The work function of the metal is 5 eV. The energy o...
The magnetic field associated with a light wave is given, at the origin, by B = B0 [sin(3.14 $$\times$$ 107)ct + sin(6.28 $$\times$$ 107)ct]. If t...
Surface of certain metal is first illuminated with light of wavelength $$\lambda$$1 = 350 nm and then, by light of wavelength $$\lambda$$2 = 540 nm....
The de-Broglie wavelength ($$\lambda$$B) associated with the electron orbiting in the second excited state of hydrogen atom is related to that in the...
If the de Broglie wavelengths associated with a proton and an $$\alpha$$-particle are equal, then the ratio of velocities of the proton and the $$\al... Two electrons are moving with non-relativistic speed perpendicular to each other. If corresponding de Broglie wavelength are$${\lambda _1}$$and$${\...
A Laser light of wavelength 660 nm is used to weld Retina detachment. If a Laser pulse of width 60 ms and power 0.5 kW is used the approximate number ...
The maximum velocity of the photoelectrons emitted from the surface is v when light of frequency n falls on a metal surface. If the incident frequency...
An electron beam is accelerated by a potential difference V to hit a metallic target to produce X–rays. It produces continuous as well as characterist...
A particle A of mass m and initial velocity v collides with a particle B of mass m/2 which is at rest. The collision is head on, and elastic. The rati...
A photoelectric surface is illuminated successively by monochromatic light of wavelengths $$\lambda$$ and $${\lambda \over 2}.$$ If the maximum kine...
When photons of wavelength $${\lambda _1}$$ are incident on an isolated sphere, the corresponding stopping potential is found to be V. When photons of...
Radiation of wavelength $$\lambda ,$$ is incident on a photocell. The fastest emitted electron has speed $$v.$$ If the wavelength is changed to $${{3\... Match List -$${\rm I}$$(Fundamental Experiment) with List -$${\rm II}$$(its conclusion) and select the correct option from the choices given below... The anode voltage of a photocell is kept fixed. The wavelength$$\lambda $$of the light falling on the cathode is gradually changed. The plate curren... This question has Statement 1 and Statement 2. Of the four choices given after the statements, choose the one that best describes the two statements. ... This question has Statement -$$1$$and Statement -$$2$$. Of the four choices given after the statements, choose the one that best describes the two ... Statement -$$1$$: When ultraviolet light is incident on a photocell, its stopping potential is$${V_0}$$and the maximum kinetic energy of the pho... If a source of power$$4kW$$produces$${10^{20}}$$photons/second, the radiation belongs to a part of the spectrum called The surface of a metal is illuminated with the light of$$400nm.$$The kinetic energy of the ejected photoelectrons was found to be$$1.68eV...
In an experiment, electrons are made to pass through a narrow slit of width $$'d'$$ comparable to their de Broglie wavelength. They are detected on a ...
Wave property of electrons implies that they will show diffraction effects. Davisson and Germer demonstrated this by diffracting electrons from crysta...
Wave property of electrons implies that they will show diffraction effects. Davisson and Germer demonstrated this by diffracting electrons from crysta...
If $${g_E}$$ and $${g_M}$$ are the accelerations due to gravity on the surfaces of the earth and the moon respectively and if Millikan's oil drop exp...
Photon of frequency $$v$$ has a momentum associated with it. If $$c$$ is the velocity of light, the momentum is
The threshold frequency for a metallic surface corresponds to an energy of $$6.2$$ $$eV$$ and the stopping potential for a radiation incident on this ...
The time taken by a photoelectron to come out after the photon strikes is approximately
The anode voltage of a photocell is kept fixed. The wavelength $$\lambda$$ of the light falling on the cathode is gradually changed. The plate curren...
If the kinetic energy of a free electron doubles, it's deBroglie wavelength changes by the factor
A photocell is illuminated by a small bright source placed $$1$$ $$m$$ away. When the same source of light is placed $${1 \over 2}$$ $$m$$ away, the n...
The work function of a substance is $$4.0$$ $$eV.$$ The longest wavelength of light that can cause photo-electron emission from this substance is app...
According to Einstein's photoelectric equation, the plot of the kinetic energy of the emitted photo electrons from a metal $$Vs$$ the frequency, of th...
Two identical photo-cathodes receive light of frequencies $${f_1}$$ and $${f_2}$$. If the velocities of the photo electrons (of mass $$m$$ ) coming ou...
Sodium and copper have work functions $$2.3$$ $$eV$$ and $$4.5$$ $$eV$$ respectively. Then the ratio of the wavelengths is nearest to

## Numerical

Nearly 10% of the power of a $$110 \mathrm{~W}$$ light bulb is converted to visible radiation. The change in average intensities of visible radiation,...
A freshly prepared radioactive source of half life 2 hours 30 minutes emits radiation which is 64 times the permissible safe level. The minimum time, ...
Two lighter nuclei combine to form a comparatively heavier nucleus by the relation given below : $${ }_{1}^{2} X+{ }_{1}^{2} X={ }_{2}^{4} Y$$ The bin...
The stopping potential for photoelectrons emitted from a surface illuminated by light of wavelength 6630 $$\mathop A\limits^o$$ is 0.42 V. If the thr...
When light of frequency twice the threshold frequency is incident on the metal plate, the maximum velocity of emitted electron is v1. When the frequen...
The K$$\alpha$$ X-ray of molybdenum has wavelength 0.071 nm. If the energy of a molybdenum atoms with a K electron knocked out is 27.5 keV, the energy...
A radioactive sample has an average life of 30 ms and is decaying. A capacitor of capacitance 200 $$\mu$$F is first charged and later connected with r...
A transistor is connected in common emitter circuit configuration, the collector supply voltage is 10 V and the voltage drop across a resistor of 1000...
A light beam of wavelength 500 nm is incident on a metal having work function of 1.25 eV, placed in a magnetic field of intensity B. The electrons emi...
A certain metallic surface is illuminated by monochromatic radiation of wavelength $$\lambda$$. The stopping potential for photoelectric current for t...
If 2.5 $$\times$$ 10$$-$$6 N average force is exerted by a light wave on a non-reflecting surface of 30 cm2 area during 40 minutes of time span, the e...
Two stream of photons, possessing energies equal to twice and ten times the work function of metal are incident on the metal surface successively. The...
The surface of a metal is illuminated alternately with photons of energies E1 = 4 eV and E2 = 2.5 eV respectively. The ratio of maximum speeds of the ...
A beam of electromagnetic radiation of intensity 6.4 × 10–5 W/cm2 is comprised of wavelength, $$\lambda$$ = 310 nm. It falls normally on a metal (wor...
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