Dual Nature of Radiation and Matter
113 JEE Physics previous year questions on Dual Nature of Radiation and Matter — options free on every question; 11 include the answer & explanation free, the rest unlock with PYQ Pass.
In an experiment with photoelectric effect, the stopping potential,
[JEE Main 2025, 29 Jan (Shift 2)]
is \(\left(\frac{1}{e}\right)\) times the maximum kinetic energy of the emitted photoelectrons
Energy of incoming photon
\(=hv=W+{K}_{\max }\)
The stopping potential \({V}_{s}\) is related to the maximum kinetic energy by:
\(e{V}_{s}={K}_{\max }\)
Correct answer is (a).
A light of wavelength ‘λ’ is incident on a metal having work function φ = 3.4 eV. The stopping potential measured for the photoelectric current setup is 1.6 eV. Find the value of λ [hc = 12400 eV Å]
(Shift - II Memory Based)
248nm
The energy of the incident photon (\(E\)) is related to the work function and the stopping potential by:
\(E=ϕ+eV\)E
Here:
- \(ϕ=3.4\text{ }\text{eV}\)
- \(eV=1.6\text{ }\text{eV}\)
- The total energy of the incident photon:
\(E=3.4+1.6=5.0\text{ }\text{eV}\)
The energy of the photon is also given by:
\(E=\frac{hc}{\lambda }\)
Rearranging for \(\lambda\):
\(\lambda =\frac{hc}{E}\)
Substitute the given values:
\(\lambda =\frac{12400}{5}=2480\text{ }\overset{˚}{\text{A}}\)
Convert to nanometers (since \(1\text{ }\overset{˚}{\text{A}}=0.1\text{ }\text{nm}\)1A˚=0.1nm):
\(\lambda =248\text{ }\text{nm}\)λ=248nm
Correct option (b) 248nm
The energy E and momentum p of a moving body of mass m are related by some equation. Given that c represents the speed of light, identify the correct equation
[JEE Main 2025, 24 Jan (Shift 2)]
\({E}^{2}={p}^{2}{c}^{2}+{m}^{2}{c}^{4}\)
\([E]={M}^{1}{L}^{2}{T}^{-2}\\ [Pc]={M}^{1}{L}^{1}{T}^{-1}\cdot {L}^{1}\\ \left[m{c}^{2}\right]={M}^{1}{L}^{2}{T}^{-2}\\ \Rightarrow [E]=[pc]=\left[m{c}^{2}\right]\)
From principle of homogenity \({E}^{2}={p}^{2}{c}^{2}+{m}^{2}{c}^{4}\)
Number of photons of equal energy emitted per second by a 6 mW laser source operating at 663 nm is ____. (Given: h = 6.63 × 10–34 Js and c = 3 × 108 m/s)
[JEE Main 2026, 28 Jan (Shift 2)]
2 × 1016
\(P=\frac{nhC}{\lambda }\)
\(6\times {10}^{−3}=\frac{n\times 6.63\times {10}^{−34}\times 3\times {10}^{8}}{663\times {10}^{−9}}\)
n = 2 \(\times\) 1016 photons
Light source having wavelength 331 nm is used to generate photo- electrons whose stopping potential is 0.2 V. The work function of the used metal in the experiment is \(\alpha \times {10}^{-19}\mathrm{J}.\) The value of \(\alpha\) is _______.
(h = 6.62 × 10⁻³⁴ Js, e = 1.6 × 10⁻¹⁹ C, c = 3 × 10⁸ m/s):
[JEE Main 2026, 5 Apr (Shift 1)]
5.68
\(\text{ (c) }ϕ=\frac{hc}{\lambda }-e{V}_{0}\)
Substituting values,
\(\frac{hc}{\lambda }=\frac{6.62\times {10}^{-34}\times 3\times {10}^{8}}{331\times {10}^{-9}}=6\times {10}^{-19}\mathrm{J}\)
\(e{V}_{0}=1.6\times {10}^{-19}\times 0.2=0.32\times {10}^{-19}\mathrm{J}\)
\(ϕ=(6-0.32)\times {10}^{-19}=5.68\times {10}^{-19}\mathrm{J}\)
Hence, the work function is
\(5.68\times {10}^{-19}\mathrm{J}\)
An electron of mass ' m ' with an initial velocity \(\vec{v}={v}_{0}\hat{i}\left({v}_{0}>0\right)\) enters an electric field \(\vec{E}=-{E}_{0}\hat{k}\). If the initial de Broglie wavelength is \({\lambda }_{0}\), the value after time t would be
[JEE Main 2025, 24 Jan (Shift 1)]
\(\frac{{\lambda }_{0}}{\sqrt{1+\frac{{e}^{2}{E}_{0}{{}^{2}t}^{2}}{{m}^{2}{{v}_{0}}^{2}}}}\)
The electron's velocity changes over time due to the electric field, therefore,
\(\vec{v}={\vec{v}}_{0}+\left(\frac{e{E}_{0}t}{m}\right)\hat{k}\)
The new wavelength is:
\({\lambda }^{'}=\frac{h}{mv}\\ {\lambda }^{'}=\frac{h}{m\sqrt{{v}_{0}^{2}+{\left(\frac{e{E}_{0}t}{m}\right)}^{2}}}\\ {\lambda }^{'}=\frac{{\lambda }_{o}}{\sqrt{1+{\left(\frac{e{E}_{0}t}{m{v}_{o}}\right)}^{2}}}where,{\lambda }_{o}=\frac{h}{m{v}_{o}}\\ {\lambda }^{'}=\frac{{\lambda }_{o}}{\sqrt{1+\left(\frac{{e}^{2}{E}_{o}^{2}{t}^{2}}{{m}^{2}{v}_{o}^{2}}\right)}}\)
In photoelectric effect an EM-wave is incident on a metal surface and electrons are ejected from the surface. If the work function of the metal is 2.14 eV and stopping potential is 2 V , what is the wavelength of the EM-wave ?
(Given \(\mathrm{hc}=1242\mathrm{eVnm}\) where h is the Planck's constant and c is the speed of light in vacuum.)
[JEE Main 2025, 23 Jan (Shift 2)]
300 nm
\(K\cdot E=e{V}_{s}\\ =2eV\\ K\cdot E\cdot =E-\Phi \\ 2=E-2.14\\ E=4.14eV\\ \frac{hc}{\lambda }=E\\ \frac{1242}{\lambda }=4.14\)
\(\lambda =300nm\)
Monochromatic light of frequency \(6 \times 10^{14} Hz\) is produced by a laser. The power emitted is \(2 \times 10^{-3} W\). How many photons per second on an average, are emitted by the source?
(Given \(h =6.63 \times 10^{-34} Js\) )
[JEE Main 2024, 01 Feb (Shift 2)]
\(5 \times 10^{15}\)
Photons are the packets of energy. Power emitted,
\(P=2 \times 10^{-3} W\)
Energy of photon,
$$$$$$\begin{aligned}& E=h v \\& =6.6 \times 10^{-34} \times 10^{14} J\end{aligned}$$$$$$
\(h\) being Planck's constant.
Number of photons emitted per second
$$$$$$\begin{aligned}& n=\frac{P}{E} \\& =\frac{2 \times 10^{-3}}{6.6 \times 10^{-34} \times 6 \times 10^{14}} \\& =5 \times 10^{15}\end{aligned}$$$$$$
Monochromatic light of frequency \(6 \times 10^{14} Hz\) is produced by a laser. The power emitted is \(2 \times 10^{-3} W\). How many photons per second on an average, are emitted by the source?
(Given \(h =6.63 \times 10^{-34} Js\) )
[JEE Main 2024, 01 Feb (Shift 2)]
\(5 \times 10^{15}\)
Photons are the packets of energy. Power emitted,
\(P=2 \times 10^{-3} W\)
Energy of photon,
$$$$$$\begin{aligned}& E=h v \\& =6.6 \times 10^{-34} \times 10^{14} J\end{aligned}$$$$$$
\(h\) being Planck's constant.
Number of photons emitted per second
$$$$$$\begin{aligned}& n=\frac{P}{E} \\& =\frac{2 \times 10^{-3}}{6.6 \times 10^{-34} \times 6 \times 10^{14}} \\& =5 \times 10^{15}\end{aligned}$$$$$$
The work functions of cesium (\(\text{Cs}\)) and lithium (\(\text{Li}\)) metals are \(1.9\text{ }\text{eV}\) and \(2.5\text{ }\text{eV}\), respectively. If light of wavelength 550 nm is incident on these two metal surfaces, for which metal(s) will the photoelectric effect occur? (Planck’s constant \(h=6.63\times 1{0}^{−34}\text{ }\text{Js}\), Speed of light \(c=3\times 1{0}^{8}\text{ }\text{m/s}\).)
[JEE Main 2025, 22 Jan (Shift 1)]
Cs only
\(\mathrm{Energy}\mathrm{associated}\mathrm{to}\lambda =550\mathrm{nm}\mathrm{is}\\ \mathrm{E}=\frac{\mathrm{h}\mathrm{c}}{\lambda }\\ \mathrm{E}=\frac{6.63\times {10}^{-34}\times 3\times {10}^{8}}{550\times {10}^{-9}}=3.61\times {10}^{-19}\mathrm{J}\\ \mathrm{E}=\frac{3.61\times {10}^{-19}}{1.6\times {10}^{-19}}=2.25\mathrm{eV}\)
This energy is more than the work function of cesium and less than the work fucntion of lithium. So photoelectric emission is possible for cesium only.
A proton of mass '\({m}_{p}\)' has same energy as that of a photon of wavelength '\(\lambda\)'. If the proton is moving at non-relativistic speed, then ratio of its de Broglie wavelength to the wavelength of photon is:
[JEE Main 2025, 28 Jan (Shift 1)]
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A photo-emissive substance is illuminated with a radiation of wavelength \({\lambda }_{\mathrm{i}}\) so that it releases electrons with de-Broglie wavelength \({\lambda }_{\mathrm{e}}\). The longest wavelength of radiation that can emit photoelectron is \({\lambda }_{0}\). Expression for de-Broglie wavelength is given by :
( m : mass of the electron, h : Planck's constant and c : speed of light)
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The work functions of cesium (\(\text{Cs}\)) and lithium (\(\text{Li}\)) metals are \(1.9\text{ }\text{eV}\) and \(2.5\text{ }\text{eV}\), respectively. If light of wavelength 550 nm is incident on these two metal surfaces, for which metal(s) will the photoelectric effect occur? (Planck’s constant \(h=6.63\times 1{0}^{−34}\text{ }\text{Js}\), Speed of light \(c=3\times 1{0}^{8}\text{ }\text{m/s}\).)
[JEE Main 2025, 22 Jan (Shift 1)]
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The threshold frequency of a metal with work function \(6.63 \ eV\) is :
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When a metal surface is illuminated by light of wavelength \(\lambda\), the stopping potential is \(9 V\). When the same surface is illuminated by light of wavelength \(2 \lambda\), stopping potential is \(3 V\). The threshold wavelength for this surface is:
[JEE Main 2024, 31 Jan (Shift 1)]
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When a metal surface is illuminated by light of wavelength \(\lambda\), the stopping potential is \(9 V\). When the same surface is illuminated by light of wavelength \(2 \lambda\), stopping potential is \(3 V\). The threshold wavelength for this surface is:
[JEE Main 2024, 31 Jan (Shift 1)]
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Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: Number of photons increases with increase in frequency of light.
Reason R: Maximum kinetic energy of emitted electrons increases with the frequency of incident radiation.
In the light of the above statements, choose the most appropriate answer from the options given below:EndFragment
[JEE Main 2024, 04 Apr (Shift 2)]EndFragment
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Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: Number of photons increases with increase in frequency of light.
Reason R: Maximum kinetic energy of emitted electrons increases with the frequency of incident radiation.
In the light of the above statements, choose the most appropriate answer from the options given below:EndFragment
[JEE Main 2024, 04 Apr (Shift 2)]EndFragment
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A sub-atomic particle of mass \({10}^{-30}\mathrm{kg}\) is moving with a velocity \(2.21\times {10}^{6}\mathrm{m}/\mathrm{s}\). Under the matter wave consideration, the particle will behave closely like ____ .\(\left(\mathrm{h}=6.63\times {10}^{-34}\mathrm{J}.\mathrm{s}\right)\)
[JEE Main 2025, 23 Jan (Shift 1)]
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The work function of a metal is \(3\mathrm{eV}\). The color of the visible light that is required to cause emission of photoelectrons is:
[JEE Main 2025, 3 Apr (Shift 1)]
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The energy E and momentum p of a moving body of mass m are related by some equation. Given that c represents the speed of light, identify the correct equation.
[JEE Main 2025, 24 Jan (Shift 2)]
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A light of wavelength ‘λ’ is incident on a metal having work function φ = 3.4 eV. The stopping potential measured for the photoelectric current setup is 1.6 eV. Find the value of λ [hc = 12400 eV Å]
(Shift - II Memory Based)
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Light is incident on a metallic plate having work function \(110\times {10}^{-20}J\). If the produced photoelectrons have zero kinetic energy then the angular frequency of the incident light is ______rad/s. (\(h=6.63\times {10}^{-34}Js\)).
[JEE Main 2026, 22 Jan (Shift 2)]
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\({K}_{1}\) and \({K}_{2}\) be the maximum kinetic energies of photoelectrons emitted from a surface of a given material for the light of wavelength \({\lambda }_{1}\) and \({\lambda }_{2}\), respectively. If \({\lambda }_{1}=2{\lambda }_{2}\) then the work function of material is given by :
[JEE Main 2026, 8 Apr (Shift 2)]
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An electron of mass ' m ' with an initial velocity \(\vec{v}={v}_{0}\hat{i}\left({v}_{0}>0\right)\) enters an electric field \(\vec{E}=-{E}_{0}\hat{k}\). If the initial de Broglie wavelength is \({\lambda }_{0}\), the value after time t would be:
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When a metal surface is illuminated by a wavelength \(\lambda\), the maximum kinetic energy of the ejected electrons is \(2\text{ }\text{eV}\). If the metal is illuminated by a wavelength \(\lambda \mathrm{/}2\), what will be the maximum kinetic energy? (Work function \(ϕ=1\text{ }\text{eV}\))
(Shift II Memory Based)
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A proton of mass '\({m}_{p}\)' has same energy as that of a photon of wavelength '\(\lambda\)'. If the proton is moving at non-relativistic speed, then ratio of its de Broglie wavelength to the wavelength of photon is.
[JEE Main 2025, 28 Jan (Shift 1)]
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The threshold frequency of a metal with work function \(6.63 \ eV\) is :
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The threshold frequency of a metal with work function \(6.63 \ eV\) is :
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A convex lens of focal length \(40 cm\) forms an image of an extended source of light on a photoelectric cell. A current I is produced. The lens is replaced by another convex lens having the same diameter but focal length \(20 cm\). The photoelectric current now is :
[JEE Main 2024, 27 Jan (Shift 1)]
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A convex lens of focal length \(40 cm\) forms an image of an extended source of light on a photoelectric cell. A current I is produced. The lens is replaced by another convex lens having the same diameter but focal length \(20 cm\). The photoelectric current now is :
[JEE Main 2024, 27 Jan (Shift 1)]
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The de Broglie wavelength of an oxygen molecule at \(27^\circ C\) is \(x\times {10}^{-12}m\). The value of \(x\) is (take Planck's constant \(=6.63\times {10}^{-34}Js\), Boltzmann constant \(=1.38\times {10}^{-23}J/K\), mass of oxygen molecule \(=5.31\times {10}^{-26}kg\))
[JEE Main 2026, 23 Jan (Shift 1)]
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UV light of \(4.13 eV\) is incident on a photosensitive metal surface having work function \(3.13 eV\). The maximum kinetic energy of ejected photoelectrons will be:
[JEE Main 2024, 09 Apr (Shift 2)]
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UV light of \(4.13 eV\) is incident on a photosensitive metal surface having work function \(3.13 eV\). The maximum kinetic energy of ejected photoelectrons will be:
[JEE Main 2024, 09 Apr (Shift 2)]
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In photoelectric experiment energy of \(2.48\mathrm{eV}\) irradiates a photo sensitive material. The stopping potential was measured to be \(0.5\mathrm{V}\). Work function of the photo sensitive material is :
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The relation between energy E and momentum p of a photon is
(Shift - II Memory based)
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An electron is travelling with a velocity v in free space and when it enters a medium, its velocity is reduced by 20%. The de Broglie wavelength of electron in the medium is \(\alpha {\lambda }_{0}\) , where \({\lambda }_{0}\) is its de Broglie wavelength in free space. The value of \(\alpha\) is______.
[JEE Main 2026, 5 Apr (Shift 2)]
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The de Broglie wavelength associated with an electron accelerated through a potential difference V is \({\lambda }_{\mathrm{e}}\) and the de Broglie wavelength associated with a proton accelerated through the same potential difference is \({\lambda }_{p}\). If their corresponding masses are \({m}_{e}\) and \({m}_{p}\), respectively, then the ratio of their de Broglie wavelengths \(\left(\frac{{\lambda }_{e}}{{\lambda }_{p}}\right)\) is ___________.
[04 April, 2026 (Shift-2)]
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Which of the following phenomena cannot be explained using the wave theory of light?
(Shift - II Memory Based)
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Which of the following phenomena can not be explained by wave theory of light?
[JEE Main 2025, 28 Jan (Shift 2)]
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The de Broglie wavelength of an oxygen molecule at 27°C is x × 10–12 m. The value of is (take Planck's constant = 6.63 × 10–34 J.s, Boltzmann constant = 1.38 × 10–23 J/K, mass of oxygen molecule = 5.31 × 10–26 kg)
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A light source of wavelength \(\lambda\) illuminates a metal surface and electrons are ejected with maximum kinetic energy of 2 eV . If the same surface is illuminated by a light source of wavelength \(\frac{\lambda }{2}\), then the maximum kinetic energy of ejected electrons will be: (The work function of metal is 1 eV )
[JEE Main 2025, 22 Jan (Shift 2)]
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A proton of mass \({m}_{p}\) has the same energy as that of a photon with wavelength λ. If the proton is moving at non-relativistic speed, find the ratio of the de Broglie wavelength of the proton to the wavelength of the photon.(Shift - I Memory Based)
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A metal target with atomic number Z = 46 is bombarded with a high energy electron beam. The emission of X-rays from the target is analyzed. The ratio r of the wavelengths of the Kα-line and the cut-off is found to be r = 2. If the same electron beam bombards another metal target with Z = 41 , the value of r will be
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Light is incident on a metallic plate having work function 110 × 10–20J. If the produced photoelectrons have zero kinetic energy then the angular frequency of the incident light is ______rad/s. (h = 6.63 × 10–34 J.s).
[JEE Main 2026, 22 Jan (Shift 2)]
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In a photoelectric effect experiment a light of frequency 1.5 times the threshold frequency is made to fall on the surface of photosensitive material. Now if the frequency is halved and intensity is doubled, the number of photo electrons emitted will be:
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The work functions of cesium (Cs) and lithium (Li) metals are 1.9 eV and 2.5 eV , respectively. If we incident a light of wavelength 550 nm on these two metal surfaces, then photo-electric effect is possible for the case of
[JEE Main 2025, 22 Jan (Shift 1)]
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The relation between energy E and momentum p of a photon is
(Shift - II Memory based)
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The work function of a substance is \(3.0 \mathrm{eV}\). The longest wavelength of light that can cause the emission of photoelectrons from this substance is approximately:
[JEE Main 2024, 30 Jan (Shift 1)]
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The work function of a substance is \(3.0 \mathrm{eV}\). The longest wavelength of light that can cause the emission of photoelectrons from this substance is approximately:
[JEE Main 2024, 30 Jan (Shift 1)]
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A proton of mass \({m}_{p}\) has the same energy as that of a photon with wavelength λ. If the proton is moving at non-relativistic speed, find the ratio of the de Broglie wavelength of the proton to the wavelength of the photon.(Shift - I Memory Based)
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In an experiment with photoelectric effect, the stopping potential:
[JEE Main 2025, 29 Jan (Shift 2)]
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In photoelectric effect an EM-wave is incident on a metal surface and electrons are ejected from the surface. If the work function of the metal is 2.14 eV and stopping potential is 2 V , what is the wavelength of the EM-wave ?
(Given \(\mathrm{hc}=1242\mathrm{eVnm}\) where h is the Planck's constant and c is the speed of light in vaccum.)
[JEE Main 2025, 23 Jan (Shift 2)]
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If E, p, m and c denote the energy, linear momentum, mass and speed of light, then the equation representing the correct relation could be
(Shift - II Memory based)
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Number of photons of equal energy emitted per second by a 6 mW laser source operating at 663 nm is ____. (Given: \(h=6.63\times {10}^{-34}Js\) and \(c=3\times {10}^{8}m/s\))
[JEE Main 2026, 28 Jan (Shift 2)]
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The work functions of cesium (Cs) and lithium (Li) metals are 1.9 eV and 2.5 eV , respectively. If we incident a light of wavelength 550 nm on these two metal surfaces, then photo-electric effect is possible for the case of
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In photoelectric experiment energy of \(2.48\mathrm{eV}\) irradiates a photo sensitive material. The stopping potential was measured to be \(0.5\mathrm{V}\). Work function of the photo sensitive material is :
[JEE Main 2024, 6 Apr (Shift I)]
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When a metal surface is illuminated by a wavelength \(\lambda\), the maximum kinetic energy of the ejected electrons is \(2\text{ }\text{eV}\). If the metal is illuminated by a wavelength \(\lambda \mathrm{/}2\), what will be the maximum kinetic energy? (Work function \(ϕ=1\text{ }\text{eV}\))
(Shift II Memory Based)
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A metal target with atomic number Z = 46 is bombarded with a high energy electron beam. The emission of X-rays from the target is analyzed. The ratio r of the wavelengths of the Kα-line and the cut-off is found to be r = 2. If the same electron beam bombards another metal target with Z = 41 , the value of r will be
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If E, p, m and c denote the energy, linear momentum, mass and speed of light, then the equation representing the correct relation could be
(Shift - II Memory based)
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An electron of mass m is moving in an electric field \(\vec{E}=-2{E}_{\mathrm{o}}\hat{i}\left({\mathrm{E}}_{\mathrm{o}}=\text{ constant }>0\right),\) with an initial velocity \(\vec{V}={v}_{\mathrm{o}}\hat{i}\left({v}_{\mathrm{o}}=\text{ constant }>\right.\)\(0)\text{. If }{\lambda }_{\mathrm{o}}=\frac{h}{4m{v}_{\mathrm{o}}}\text{, }\) its de Broglie wavelength at time t is ________. (e = charge of electron).
[JEE Main 2026, 5 Apr (Shift 1)]
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In photoelectric effect, the stopping potential \(\left({V}_{0}\right)\)v/s frequency (\(\nu\)) curve is plotted.
( h is the Planck's constant and \({ϕ}_{0}\) is work function of metal)
(A) \({V}_{0}\) v/s \(\nu\) is linear.
(B) The slope of \({V}_{0}\) v/s \(\nu\) curve \(=\frac{{ϕ}_{0}}{h}\)
(C) h constant is related to the slope of \({V}_{0}\) v/s \(\nu\) line.
(D) The value of electric charge of electron is not required to determine h using the \({V}_{0}\) v/s \(\nu\) curve.
(E) The work function can be estimated without knowing the value of h.
Choose the correct answer from the options given below :
[JEE Main 2025, 24 Jan (Shift 2)]
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A photo-emissive substance is illuminated with a radiation of wavelength \({\lambda }_{\mathrm{i}}\) so that it releases electrons with de-Broglie wavelength \({\lambda }_{\mathrm{e}}\). The longest wavelength of radiation that can emit photoelectron is \({\lambda }_{0}\). Expression for de-Broglie wavelength is given by :
( m : mass of the electron, h : Planck's constant and c : speed of light)
[JEE Main 2025, 7 Apr (Shift 2)]
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Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: In photoelectric effect, on increasing the intensity of incident light the stopping potential increases.
Reason R : Increase in intensity of light increases the rate of photoelectrons emitted, provided the frequency of incident light is greater than threshold frequency.
In the light of the above statements, choose the correct answer from the options given below:
[JEE Main 2025, 4 Apr (Shift 1)]
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A sub-atomic particle of mass \({10}^{-30}\mathrm{kg}\) is moving with a velocity \(2.21\times {10}^{6}\mathrm{m}/\mathrm{s}\). Under the matter wave consideration, the particle will behave closely like ____ .\(\left(\mathrm{h}=6.63\times {10}^{-34}\mathrm{J}.\mathrm{s}\right)\)
[JEE Main 2025, 23 Jan (Shift 1)]
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The de Broglie wavelengths of a proton and an \(\alpha\) particle are \(\lambda\) and \(2 \lambda\) respectively. The ratio the velocities of proton and \(\alpha\) particle will be :
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Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Emission of electrons in photoelectric effect can be suppressed by applying a sufficiently negative electron potential to the photoemissive substance.
Reason (R) : A negative electric potential, which stops the emission of electrons from the surface of a photoemissive substance, varies linearly with frequency of incident radiation.
In the light of the above statements, choose the most appropriate answer from the options given below :
[JEE Main 2025, 29 Jan (Shift 1)]
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For a certain metal, when monochromatic light of wavelength \(\lambda\) is incident, the stopping potential for photoelectrons is \(3{V}_{0}\). When the same metal is illuminated by light of wavelength \(2\lambda\), then the stopping potential becomes \({V}_{0}\). The threshold wavelength for photoelectric emission for the given metal is \(\alpha \lambda\). The value of \(\alpha\) is
[JEE Main 2026, 2 Apr (Shift 1)]
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Which of the following phenomena cannot be explained using the wave theory of light?
(Shift - II Memory Based)
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A light source of wavelength \(\lambda\) illuminates a metal surface and electrons are ejected with maximum kinetic energy of 2 eV . If the same surface is illuminated by a light source of wavelength \(\frac{\lambda }{2}\), then the maximum kinetic energy of ejected electrons will be (The work function of metal is 1 eV )
[JEE Main 2025, 22 Jan (Shift 2)]
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The threshold wavelength for photoelectric emission from a material is 5500 Å. Photoelectrons will be emitted, when this material is illuminated with monochromatic radiation from a
A. \(75 W\) infra-red lamp
B. \(10 W\) infra-red lamp
C. \(75 W\) ultra-violet lamp
D. \(10 W\) ultra-violet lamp
Choose the correct answer from the options given below:
[JEE Main 2023, 29 Jan (Shift I)]
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Given below are two statements: one is labelled as Assertion (A) and the other is labeled as Reason (R).
Assertion (A): An electron microscope achieve better resolving power than an optical microscope.
Reason (R): The de Broglie's wavelength of the electrons emitted from an electron gun is much less than wavelength of visible light.
In the light of the above statements, choose the correct answer from the options given below :
[JEE Main 2021, 26 Feb (Shift 1)]
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A moving proton and electron have the same de-Broglie wavelength. If \(K\) and \(P\) denote the K.E. and momentum respectively. Then choose the correct option.
[JEE Main 2021, 31 Aug (Shift 1)]
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If the two metals \(A\) and \(B\) are exposed to radiation of wavelength \(350 nm\). The work functions of metals \(A\) and \(B\) are \(4.8 eV\) and \(2.2 eV\). Then choose the correct option
[JEE Main 2023, 31 Jan (Shift 2)]
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An \(\alpha\)-particle, a proton and an electron have the same kinetic energy. Which one of the following is correct in case of their De-Broglie wavelength:
[JEE Main 2023, 24 Jan (Shift 2)]
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The kinetic energy of an electron, \(\alpha\)-particle and a proton are given as \(4 K, 2 K\) and \(K\) respectively. The de-Broglie wavelength associated with electron \(\left(\lambda_e\right) \alpha\)-particle \(\left(\lambda_\alpha\right)\) and the proton \(\left(\lambda_p\right)\) are as follows:
[JEE Main 2023, 6 Apr (Shift 1)]
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The threshold wavelength for photoelectric emission from a material is 5500\(\overset{o}{A}\). Photoelectrons will be emitted, when this material is illuminated with monochromatic radiation from a
A. \(75 W\) infra-red lamp
B. \(10 W\) infra-red lamp
C. \(75 W\) ultra-violet lamp
D. \(10 W\) ultra-violet lamp
Choose the correct answer from the options given below:
[JEE Main 2023, 29 Jan (Shift 1)]
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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 stopping voltage if the source light is changed with another source of wavelength of \(474.6 nm\) ?
[JEE Main 2021, 27 Aug (Shift 2)]
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A metallic surface is illuminated with radiation of wavelength \(\lambda\), the stopping potential is \(V_{0^*}\) If the same surface is illuminated with radiation of wavelength \(2 \lambda\), the stopping potential becomes \(\frac{V_o}{4}\). The threshold wavelength for this metallic surface will be
[JEE Main 2023, 11 Apr (Shift 1)]
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Light of frequency \( 1.5 \) times the threshold frequency is incident on a photosensitive material. What will be the photoelectric current if the frequency is halved and intensity is doubled?
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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:
\[\begin{aligned}& {\left[m_e=\text { mass of electron }=9 \times 10^{-31} kg \right.} \\& h=\text { Planck constant }=6.6 \times 10^{-34} JS \\& \left.k_B=\text { Boltzmann constant }=1.38 \times 10^{-23} JK ^{-1}\right]\end{aligned}\]
[JEE Main 2021, 1 Sep (Shift 2)]
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If the ratio of de-Broglie wavelength of an \(\alpha\)-particle and a proton accelerated from rest by the same potential is \(\frac{1}{\sqrt{m}}\), then the value of \(m\) is
[JEE Main 2023, 29 Jan (Shift 2)]
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An electron (mass \( =m_{\mathrm{e}} \) ) and proton (mass \( =1836 m_{\mathrm{e}} \) ) are moving with the same speed. The ratio of their de Broglie wavelength \( \lambda_{\text {electron }} / \lambda_{\text {proton }} \) will be:
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The ratio of the de-Broglie wavelengths of proton and electron having same kinetic energy:
(Assume \(m_{ p }=m_{ e } \times 1849\) )
[JEE Main 2023, 11 Apr (Shift 2)]
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The kinetic energy of an electron, \(\alpha\)-particle and a proton are given as \(4 K, 2 K\) and \(K\) respectively. The de-Broglie wavelength associated with electron \(\left(\lambda_e\right) \alpha\)-particle \(\left(\lambda_\alpha\right)\) and the proton \(\left(\lambda_n\right)\) are as follows:
[JEE Main 2023, 6 Apr (Shift 1)]
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Given below are two statements:
Statement-I: Out of microwaves, infrared rays and ultraviolet rays, ultraviolet rays are the most effective for the emission of electrons from a metallic surface.
Statement-II: Above the threshold frequency, the maximum kinetic energy of photoelectrons is inversely proportional to the frequency of the incident light.
In the light of above statements, choose the correct answer from the options given below.
[JEE Main 2023, 13 Apr (Shift 2)]
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The de Broglie wavelength of an electron having kinetic energy \(E\) is \(\lambda\). If the kinetic energy of electron becomes \(\frac{E}{4}\), then its de-Broglie wavelength will be:
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The threshold wavelength for photoelectric emission from a material is \(5500\overset{^\circ }{A}\). Photoelectrons will be emitted, when this material is illuminated with monochromatic radiation from a
A. 75 W infra-red lamp
B. 10 W infra-red lamp
C. 75 W ultra-violet lamp
D. 10 W ultra - violet lamp
Choose the correct answer from the options given below :
[JEE Main 2023, 29 Jan (Shift 1)]2
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The difference between threshold wavelengths for two metal surfaces \(A\) and \(B\) having work function \(\phi_A=9 eV\) and \(\phi_B=4.5 eV\) in \(nm\) is:
(Given, hc \(=1242 eV nm ) \quad\)
[JEE Main 2023, 13 Apr (Shift I)]
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If the two metals \(A\) and \(B\) are exposed to radiation of wavelength \(350 nm\). The work functions of metals \(A\) and \(B\) are \(4.8 eV\) and \(2.2 eV\). Then choose the correct option.
[JEE Main 2023, 31 Jan (Shift 2)]
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The threshold frequency of metal is \(f_0\). When the light of frequency \(2 f_0\) is incident on the metal plate, the maximum velocity of photoelectron is \(v_1\). When the frequency of incident radiation is increased to \(5 f_0\), the maximum velocity of photoelectrons emitted is \(v_2\). The ratio of \(v_1\) to \(v_2\) is:
[JEE Main 2023, 1 Feb (Shift 2)]
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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-Broglie wavelength reduces to \(75 \%\) of the initial value?
[JEE Main 2021, 26 Aug (Shift 2)]
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Proton (p) and electron (e) will have same de Broglie wavelength when the ratio of their momentum is (assume, \(\left.m_{ p }=1849 m_{ e }\right)\)
[JEE Main 2023, 8 Apr (Shift 1)]
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If a source of electromagnetic radiation having power \(15 kW\) produces \(10^{16}\) photons per second, the radiation belongs to a part of spectrum is: (Take Planck constant \(h=6 \times 10^{-34} Js\) )
[JEE Main 2023, 31 Jan (Shift I)]
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Given below are two statements: one is labelled as Assertion (A) and the other is labeled as Reason (R).
Assertion (A): An electron microscope achieves better resolving power than an optical microscope.
Reason (R): The de Broglie's wavelength of the electrons emitted from an electron gun is much less than wavelength of visible light.
In the light of the above statements, choose the correct answer from the options given below :
[JEE Main 2021, 26 Feb (Shift 1)]
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The de Broglie wavelength of an electron having kinetic energy \(E\) is \(\lambda\). If the kinetic energy of electron becomes \(\frac{E}{4}\), then its de-Broglie wavelength will be:
[JEE Main 2024, 29 Jan (Shift 1)]
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An \(\alpha\) particle and a proton are accelerated from rest by a potential difference of \(100 V\). After this, their de Broglie wavelengths are \(\lambda_\alpha\) and \(\lambda_P\) respectively. The ratio \(\frac{\lambda_P}{\lambda_\alpha}\) is:
[JEE Main 2021, 25 Feb (Shift 1)]
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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 de-Broglie wavelength increases by \(50 \%\). The value of \(\left(\frac{V_1}{V_2}\right)\) is equal to:
[JEE Main 2021, 27 Jul (Shift 1)]
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A particle is travelling 4 times as fast as an electron. Assuming the ratio of de-Broglie wavelength of a particle to that of electron is \(2: 1\), the mass of the particle is:
[JEE Main 2021, 18 Mar (Shift 1)]
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The stopping potential in the context of photoelectric depends on the following property of incident electromagnetic radiation:
[JEE Main 2021, 16 Mar (Shift I)]
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The de Broglie wavelength of a molecule in a gas at room temperature \((300 K)\) is \(\lambda_1\). If the temperature of the gas is increased to \(600 K\), then the de Broglie wavelength of the same gas molecule becomes:
[JEE Main 2023, 10 Apr (Shift 1)]
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An electron moving with speed \(v\) and a photon moving with speed \(c\), have same de Broglie wavelength. The ratio of kinetic energy of electron to that of photon is:
[JEE Main 2021, 25 Jul (Shift 2)]
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From the photoelectric effect experiment, following observations are made. Identify which of these are correct
A. The stopping potential depends only on the work function of the metal.
B. The saturation current increases as the intensity of incident light increases.
C. The maximum kinetic energy of a photo electron depends on the intensity of the incident light.
D. Photoelectric effect can be explained using wave theory of light.
Choose the correct answer from the options given below:
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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 wavelength of this electron at time \( t \) ignoring relativistic effects is:
[JEE Main 2020, 9 Jan (Shift 2)]
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Which of the following are true?
A. Speed of light in vacuum is dependent on the direction of propagation.
B. Speed of light in a medium is independent of the wavelength of light.
C. The speed of light is independent of the motion of the source.
D. The speed of light in a medium is independent of intensity.
Choose the correct answer from the options given below:
[JEE Main 2023, 29 Jan (Shift I)]
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The work functions of Aluminium and Gold are \(4.1 eV\) and \(5.1 eV\) respectively. The ratio of the slope of the stopping potential versus frequency plot for Gold to that of Aluminium is
[JEE Main 2023, 6 Apr (Shift 1)]
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In photo electric effect
A. The photocurrent is proportional to the intensity of the incident radiation.
B. Maximum Kinetic energy with which photoelectrons are emitted depends on the intensity of incident light.
C. Max. K.E with which photoelectrons are emitted depends on the frequency of incident light.
D. The emission of photoelectrons require a minimum threshold intensity of incident radiation.
E. Max. K.E of the photoelectrons is independent of the frequency of the incident light.
Choose the correct answer from the options given below:
[JEE Main 2023, 8 Apr (Shift II)]
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If a source of electromagnetic radiation having power 15kW produces \({10}^{16}\) photons per second, the radiation belongs to a part of spectrum is.
(Take Planck constant h = 6 × 10–34 Js)
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A proton and an \(\alpha\)-particle are accelerated from rest by \(2 V\) and \(4 V\) potentials, respectively. The ratio of their de Broglie wavelength is:
[JEE Main 2023, 12 Apr (Shift 1)]
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The threshold frequency of a metal is \(f0\). When the light of frequency \(2{f}_{0}\) is incident on the metal plate, the maximum velocity of photoelectrons is \({v}_{1}\). When the frequency of incident radiation is increased to \(5{f}_{0}\). The maximum velocity of photoelectrons emitted is \({v}_{2}\). The ratio of \({v}_{2}\). The ratio of \({v}_{1}\) to \({v}_{2}\) is:
[JEE Main 2023, 1 Feb (Shift 2)]
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Given below are two statements:
Statement-I: Stopping potential in photoelectric effect does not depend on the power of the light source.
Statement-II: For a given metal, the maximum kinetic energy of the photoelectron depends on the wavelength of the incident light.
In light of the above statements, choose the most appropriate answer from the options given below.
[JEE Main 2023, 25 Jan (Shift 2)]
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If the ratio of de-Broglie wavelength of an \(\alpha\)-particle and a proton accelerated from rest by the same potential is: \(\frac{1}{\sqrt{m}}\), then the value of \(m\) is \(\quad\)
[JEE Main 2023, 29 Jan (Shift 2)]
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