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MCQ (Single Correct Answer)

JEE Main 2024 (Online) 1st February Evening Shift
The number of radial node/s for $3 p$ orbital is :
JEE Main 2024 (Online) 1st February Morning Shift
In case of isoelectronic species the size of $\mathrm{F}^{-}, \mathrm{Ne}$ and $\mathrm{Na}^{+}$is affected by :
JEE Main 2024 (Online) 1st February Morning Shift
According to the wave-particle duality of matter by de-Broglie, which of the following graph plot presents most appropriate relationship between wavel...
JEE Main 2024 (Online) 31st January Evening Shift
The four quantum numbers for the electron in the outer most orbital of potassium (atomic no. 19) are
JEE Main 2024 (Online) 30th January Morning Shift
Given below are two statements : Statement (I) : The orbitals having same energy are called as degenerate orbitals. Statement (II) : In hydrogen atom,...
JEE Main 2024 (Online) 29th January Evening Shift
Match List I with List II .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border-style:solid;border-width:1px;font-family...
JEE Main 2024 (Online) 29th January Morning Shift
The correct set of four quantum numbers for the valence electron of rubidium atom $$(\mathrm{Z}=37)$$ is :
JEE Main 2023 (Online) 15th April Morning Shift
Given below are two statements: Statement I : According to Bohr's model of hydrogen atom, the angular momentum of an electron in a given stationary s...
JEE Main 2023 (Online) 13th April Morning Shift
The energy of an electron in the first Bohr orbit of hydrogen atom is $$-2.18 \times 10^{-18} \mathrm{~J}$$. Its energy in the third Bohr orbit is ___...
JEE Main 2023 (Online) 11th April Morning Shift
Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R : Assertion A : In the photoelectric effect, the...
JEE Main 2023 (Online) 8th April Evening Shift
Henry Moseley studied characteristic X-ray spectra of elements. The graph which represents his observation correctly is Given $$v=$$ frequency of $$\m...
JEE Main 2023 (Online) 6th April Evening Shift
If the radius of the first orbit of hydrogen atom is $$\alpha_{0}$$, then de Broglie's wavelength of electron in $$3^{\text {rd }}$$ orbit is :
JEE Main 2023 (Online) 1st February Evening Shift
Which one of the following sets of ions represents a collection of isoelectronic species? (Given : Atomic Number : $$\mathrm{F:9,Cl:17,Na=11,Mg=12,Al=...
JEE Main 2023 (Online) 31st January Evening Shift
Arrange the following orbitals in decreasing order of energy. A. $\mathrm{n}=3, \mathrm{l}=0, \mathrm{~m}=0$ B. $\mathrm{n}=4, \mathrm{l}=0, \mathrm{~...
JEE Main 2023 (Online) 31st January Morning Shift
Which transition in the hydrogen spectrum would have the same wavelength as the Balmer type transition from $$\mathrm{n=4}$$ to $$\mathrm{n}=2$$ of $$...
JEE Main 2023 (Online) 30th January Evening Shift
Maximum number of electrons that can be accommodated in shell with $n=4$ are:
JEE Main 2023 (Online) 30th January Evening Shift
The wave function $(\Psi)$ of $2 \mathrm{~s}$ is given by $$ \Psi_{2 \mathrm{~s}}=\frac{1}{2 \sqrt{2 \pi}}\left(\frac{1}{a_0}\right)^{1 / 2}\left(2-\f...
JEE Main 2023 (Online) 29th January Morning Shift
The shortest wavelength of hydrogen atom in Lyman series is $$\lambda$$. The longest wavelength is Balmer series of He$$^+$$ is
JEE Main 2023 (Online) 25th January Morning Shift
The radius of the $$\mathrm{2^{nd}}$$ orbit of $$\mathrm{Li^{2+}}$$ is $$x$$. The expected radius of the $$\mathrm{3^{rd}}$$ orbit of $$\mathrm{Be^{3+...
JEE Main 2023 (Online) 24th January Evening Shift
The number of s-electrons present in an ion with 55 protons in its unipositive state is
JEE Main 2023 (Online) 24th January Morning Shift
The magnetic moment of a transition metal compound has been calculated to be 3.87 B.M. The metal ion is
JEE Main 2023 (Online) 24th January Morning Shift
It is observed that characteristic X-ray spectra of elements show regularity. When frequency to the power "n" i.e. $${v^n}$$ of X-rays emitted is plot...
JEE Main 2022 (Online) 29th July Evening Shift
Given below are the quantum numbers for 4 electrons. A. $$\mathrm{n}=3,l=2, \mathrm{~m}_{1}=1, \mathrm{~m}_{\mathrm{s}}=+1 / 2$$ B. $$\mathrm{n}=4,l=1...
JEE Main 2022 (Online) 28th July Evening Shift
Given below are two statements: One is labelled as Assertion $$\mathbf{A}$$ and the other is labelled as Reason $$\mathbf{R}$$ Assertion $$\mathbf{A}$...
JEE Main 2022 (Online) 28th July Morning Shift
Identify the incorrect statement from the following.
JEE Main 2022 (Online) 27th July Evening Shift
The correct decreasing order of energy for the orbitals having, following set of quantum numbers : (A) n = 3, l = 0, m = 0 (B) n = 4, l = 0, m = 0 (C)...
JEE Main 2022 (Online) 27th July Evening Shift
Outermost electronic configurations of four elements A, B, C, D are given below : (A) $$3 s^{2}$$ (B) $$3 s^{2} 3 p^{1}$$ (C) $$3 s^{2} 3 p^{3}$$ (D) ...
JEE Main 2022 (Online) 27th July Morning Shift
Given below are two statements. One is labelled as Assertion A and the other is labelled as Reason R. Assertion A: Energy of $$2 \mathrm{s}$$ orbital ...
JEE Main 2022 (Online) 25th July Morning Shift
Which of the following sets of quantum numbers is not allowed?
JEE Main 2022 (Online) 30th June Morning Shift
The number of radial nodes and total number of nodes in 4p orbital respectively are :
JEE Main 2022 (Online) 29th June Evening Shift
Which of the following is the correct plot for the probability density $${\psi ^2}$$ (r) as a function of distance 'r' of the electron from the nucleu...
JEE Main 2022 (Online) 29th June Morning Shift
Which of the following statements are correct? (A) The electronic configuration of Cr is [Ar] 3d5 4s1. (B) The magnetic quantum number may have a nega...
JEE Main 2022 (Online) 28th June Evening Shift
Consider the following statements : (A) The principal quantum number 'n' is a positive integer with values of 'n' = 1, 2, 3, ... (B) The azimuthal qua...
JEE Main 2022 (Online) 26th June Evening Shift
The number of radial and angular nodes in 4d orbital are, respectively
JEE Main 2022 (Online) 26th June Morning Shift
If the radius of the 3rd Bohr's orbit of hydrogen atom is r3 and the radius of 4th Bohr's orbit is r4. Then :...
JEE Main 2022 (Online) 25th June Evening Shift
The minimum energy that must be possessed by photons in order to produce the photoelectric effect with platinum metal is : [Given : The threshold freq...
JEE Main 2022 (Online) 25th June Morning Shift
The pair, in which ions are isoelectronic with AI3+ is :
JEE Main 2022 (Online) 24th June Evening Shift
The energy of one mole of photons of radiation of wavelength 300 nm is (Given : h = 6.63 $$\times$$ 10$$-$$34 J s, NA = 6.02 $$\times$$ 1023 mol$$-$$1...
JEE Main 2022 (Online) 24th June Morning Shift
Consider the following pairs of electrons (A) (a) n = 3, $$l$$ = 1, m1 = 1, ms = + $${1 \over 2}$$       (b) n = 3, 1 = ...
JEE Main 2021 (Online) 26th August Morning Shift
Given below are two statements.Statement I : According to Bohr's model of an atom, qualitatively the magnitude of velocity of electron increases with ...
JEE Main 2021 (Online) 27th July Evening Shift
If the Thompson model of the atom was correct, then the result of Rutherford's gold foil experiment would have been :
JEE Main 2021 (Online) 27th July Morning Shift
Given below are two statements :Statement I : Rutherford's gold foil experiment cannot explain the line spectrum of hydrogen atom.Statement II : Bohr'...
JEE Main 2021 (Online) 20th July Evening Shift
Outermost electronic configuration of a group 13 element, E, is 4s2, 4p1. The electronic configuration of an element of p-block period-five placed dia...
JEE Main 2021 (Online) 18th March Evening Shift
Given below are two statements :Statement I : Bohr's theory accounts for the stability and line spectrum of Li+ ion.Statement II : Bohr's theory was u...
JEE Main 2021 (Online) 18th March Morning Shift
The ionic radius of Na+ ions is 1.02 $$\mathop A\limits^o $$. The ionic radii (in $$\mathop A\limits^o $$) of Mg2+ and Al3+, respectively, are ...
JEE Main 2021 (Online) 18th March Morning Shift
A certain orbital has no angular nodes and two radial nodes. The orbital is :
JEE Main 2021 (Online) 26th February Evening Shift
Which of the following forms of hydrogen emits low energy $$\beta$$- particles?
JEE Main 2021 (Online) 26th February Morning Shift
The orbital having two radial as well as two angular nodes is :
JEE Main 2021 (Online) 25th February Morning Shift
The plots of radial distribution functions for various orbitals of hydrogen atom against 'r' are given below : The correct plot for 3s orbital is :...
JEE Main 2021 (Online) 24th February Evening Shift
According to Bohr's atomic theory :(A) Kinetic energy of electron is $$ \propto {{{Z^2}} \over {{n^2}}}$$.(B) The product of velocity (v) of electron ...
JEE Main 2020 (Online) 5th September Evening Slot
The correct statement about probability density (except at infinite distance from nucleus) is :
JEE Main 2020 (Online) 5th September Morning Slot
The difference between the radii of 3rd and 4th orbits of Li2+ is R1 . The difference between the radii of 3rd and 4th orbits of He+ is $$\Delta $$R2 ...
JEE Main 2020 (Online) 4th September Evening Slot
The shortest wavelength of H atom in the Lyman series is $$\lambda $$1. The longest wavelength in the Balmar series of He+ is :
JEE Main 2020 (Online) 4th September Morning Slot
The region in the electromagnetic spectrum where the Balmar series lines appear is :
JEE Main 2020 (Online) 3rd September Evening Slot
Consider the hypothetical situation where the azimuthal quantum number, $$l$$, takes values 0, 1, 2, ....., n + 1, where n is the principal quantum nu...
JEE Main 2020 (Online) 2nd September Evening Slot
The number of subshells associated with n = 4 and m = –2 quantum numbers is
JEE Main 2020 (Online) 2nd September Morning Slot
The figure that is not a direct manifestation of the quantum nature of atoms is :
JEE Main 2020 (Online) 9th January Morning Slot
The de Broglie wavelength of an electron in the 4th Bohr orbit is :
JEE Main 2020 (Online) 8th January Evening Slot
The radius of the second Bohr orbit, in terms of the Bohr radius, a0, in Li2+ is :
JEE Main 2020 (Online) 8th January Evening Slot
Hydrogen has three isotopes (A), (B) and (C). If the number of neutron(s) in (A), (B) and (C) respectively, are (x), (y) and (z), the sum of (x), (y) ...
JEE Main 2020 (Online) 8th January Morning Slot
For the Balmer series in the spectrum of H atom, $$\overline \nu = {R_H}\left\{ {{1 \over {n_1^2}} - {1 \over {n_2^2}}} \right\}$$, the correct stat...
JEE Main 2020 (Online) 7th January Morning Slot
The number of orbitals associated with quantum number n = 5, ms = +$${1 \over 2}$$ is :
JEE Main 2019 (Online) 12th April Morning Slot
The electrons are more likely to be found : ...
JEE Main 2019 (Online) 12th April Morning Slot
The group number, number of valence electrons, and valency of an element with atomic number 15, respectively, are:
JEE Main 2019 (Online) 10th April Evening Slot
The ratio of the shortest wavelength of two spectral series of hydrogen spectrum is found to be about 9. The spectral series are :
JEE Main 2019 (Online) 10th April Morning Slot
The isoelectronic set of ions is :
JEE Main 2019 (Online) 10th April Morning Slot
The graph between $${\left| \psi \right|^2}$$ and r (radial distance) is shown below. This represents : ...
JEE Main 2019 (Online) 9th April Evening Slot
Which one of the following about an electron occupying the 1s orbital in a hydrogen atom is incorrect ? (The Bohr radius is represented by a0)...
JEE Main 2019 (Online) 9th April Morning Slot
For any given series of spectral lines of atomic hydrogen, let $$\Delta \mathop v\limits^\_ = $$ $$\Delta {\overline v _{\max }} - \Delta {\overline ...
JEE Main 2019 (Online) 8th April Evening Slot
If p is the momentum of the fastest electron ejected from a metal surface after the irradiation of light having wavelength $$\lambda $$, then for 1.5 ...
JEE Main 2019 (Online) 8th April Morning Slot
The quantum number of four electrons are given below : n = 4, l = 2, ml =–2, ms = –1/2 n = 3, l = 2, ml = 1, ms = +1/2 n = 4, l = 1, ml = 0, ms = +1/2...
JEE Main 2019 (Online) 12th January Evening Slot
If the de Broglie wavelength of the electron in nth Bohr orbit in a hydrogenic atom is equal to 1.5 $$\pi $$a0 (a0 is Bohr radius), then the value of ...
JEE Main 2019 (Online) 12th January Evening Slot
The upper stratosphere consisting of the ozone layer protects us from sun's radiation that falls in the wavelength region of -
JEE Main 2019 (Online) 12th January Morning Slot
What is the work function of the metal if the light of wavelength 4000$$\mathop A\limits^ \circ $$ generates photoelectrons of velocity 6 $$ \times $...
JEE Main 2019 (Online) 11th January Evening Slot
The de Broglie wavelength ($$\lambda $$) associated with a photoelectron varies with the frequency (v) of the incident radiation as, [v0 is threshold ...
JEE Main 2019 (Online) 11th January Morning Slot
Heat treatment of muscular pain involves radiation of wavelength of about 900 nm. Which spectral line of H atom is suitable for this purpose? [RH = 1 ...
JEE Main 2019 (Online) 10th January Evening Slot
The ground state energy of hydrogen atom is – 13.6 eV. The energy of second excited state of He+ ion in eV is :
JEE Main 2019 (Online) 10th January Morning Slot
Which of the graphs shown below does not represent the relationship between incident light and the electron ejected from metal surface ?
JEE Main 2019 (Online) 9th January Evening Slot
Which of the following combination of statements is true regarding the interpretation of the atomic orbitals ? (a) An electron in an orbital of high ...
JEE Main 2019 (Online) 9th January Morning Slot
The highest value of the calculated spin only magnetic moment (in BM) among all the transition metal complexes is :
JEE Main 2019 (Online) 9th January Morning Slot
For emission line of atomic hydrogen from ni = 8 to nf = n, the plot of wave number $$\left( {\overline v } \right)$$ against $$\left( {{1 \over {{n^2...
JEE Main 2018 (Online) 16th April Morning Slot
Which of the following statements is false ?
JEE Main 2018 (Online) 15th April Evening Slot
The de-Broglie's wavelength of electron present in first Bohr orbit of 'H' atom is :
JEE Main 2018 (Online) 15th April Morning Slot
Ejection of the photoelectron from metal in the photoelectric experiment can be stopped by applying 0.5 V when the radiation of 250 nm is used. The wo...
JEE Main 2017 (Online) 9th April Morning Slot
The electron in the hydrogen atom undergoes transition from higher orbitals to orbital of radius 211.6 pm. This transition is associated with :
JEE Main 2017 (Online) 8th April Morning Slot
If the shortest wavelength in Lyman series of hydrogen atom is A, then the longestwavelength in Paschen series of He+ is :
JEE Main 2017 (Offline)
The radius of the second Bohr orbit for hydrogen atom is: (Planck’s Const. h = 6.6262 × 10-34 Js; mass of electron = 9.1091 × 10-31 kg; charge of elec...
JEE Main 2017 (Offline)
The group having isoelectronic species is:
JEE Main 2016 (Online) 9th April Morning Slot
The total number of orbitals associated with the principal quantum number 5 is :
JEE Main 2016 (Offline)
A stream of electrons from a heated filament was passed between two charged plates kept at a potential difference V esu. If e and m are charge and mas...
JEE Main 2015 (Offline)
Which of the following is the energy of a possible excited state of hydrogen?
JEE Main 2014 (Offline)
The correct set of four quantum numbers for the valence elections of rubidium atom (Z= 37) is:
JEE Main 2013 (Offline)
Energy of an electron is given by $$E = - 2.178 \times {10^{ - 18}}J\left( {{{{Z^2}} \over {{n^2}}}} \right)$$. Wavelength of light required to excit...
AIEEE 2012
The electrons identified by quantum numbers n and l : (a) n = 4, $$l$$ = 1 (b) n = 4, $$ l$$ = 0 (c) n = 3, $$l$$ = 2 (d) n = 3, $$l$$ = 1 Can be plac...
AIEEE 2011
A gas absorbs a photon of 355 nm and emits at two wavelengths. If one of the emissions is at 680 nm, the other is at :
AIEEE 2010
The energy required to break one mole of Cl–Cl bonds in Cl2 is 242 kJ mol–1. The longest wavelength of light capable of breaking a single Cl – Cl bond...
AIEEE 2010
Ionisation energy of He+ is 19.6 x 10–18 J atom–1. The energy of the first stationary state (n = 1) of Li2+ is...
AIEEE 2009
Calculate the wavelength (in nanometer) associated with a proton moving at 1.0 x 103 ms−1 (Mass of proton = 1.67 $$\times$$ 10-27 kg and h = 6.63 $$...
AIEEE 2009
In an atom, an electron is moving with a speed of 600 m/s with an accuracy of 0.005%. Certainity with which the position of the electron can be locate...
AIEEE 2008
Which one of the following constitutes a group of the isoelectronic species?
AIEEE 2008
The ionization enthalpy of hydrogen atom is 1.312 × 106 J mol−1. The energy required to excite the electron in the atom from n = 1 to n = 2 is ...
AIEEE 2007
Which of the following sets of quantum numbers represents the highest energy of an atom?
AIEEE 2006
According to Bohr's theory, the angular momentum of an electron in 5th orbit is
AIEEE 2006
Uncertainty in the position of an electron (mass = 9.1 $$\times$$ 10-31 kg) moving with a velocity 300 ms-1, accurate upto 0.001% will be (h = 6.63 $$...
AIEEE 2006
Which of the following sets of ions represents a collection of isoelectronic species?
AIEEE 2005
Of the following sets which one does NOT contain isoelectronic species?
AIEEE 2005
In a multi-electron atom, which of the following orbitals described by the three quantum members will have the same energy in the absence of magnetic ...
AIEEE 2005
Pick out the isoelectronic structure from the following : $$\eqalign{ & \left( i \right)\,\,\,\,\,\,C{H_3}^ + \cr & \left( {ii} \right...
AIEEE 2004
Which of the following sets of quantum numbers is correct for an electron in 4f orbital?
AIEEE 2004
Consider the ground state of Cr atom (Z = 24). The number of electrons with the azimuthal quantum numbers, l = 1 and 2 are respectively
AIEEE 2004
The wavelength of the radiation emitted when in a hydrogen atom electron falls from infinity to stationary state 1, would be (Rydberg constant = 1.09...
AIEEE 2004
Which one of the following sets of ions represents the collection of isoelectronic species? (Atomic nos. : F = 9, Cl = 17, Na = 11, Mg = 12, Al = 13, ...
AIEEE 2003
The orbital angular momentum for an electron revolving in an orbit is given by $$\sqrt {l(l + 1)} {h \over {2\pi }}$$. This momentum for an s-electron...
AIEEE 2003
Which one of the following groupings represents a collection of isoelectronic species? (At. nos. : Cs : 55, Br : 35)
AIEEE 2003
In Bohr series of lines of hydrogen spectrum, the third line from the red end corresponds to which one of the following inter-orbit jumps of the elect...
AIEEE 2003
The de Broglie wavelength of a tennis ball of mass 60 g moving with a velocity of 10 meters per second is approximately
AIEEE 2002
In a hydrogen atom, if energy of an electron in ground state is -13.6 eV, then that in the 2nd excited state is
AIEEE 2002
Uncertainty in position of a minute particle of mass 25 g in space is 10-5 m. What is the uncertainty in its velocity (in ms-1) (h = 6.6 $$\times$$ 10...

Numerical

JEE Main 2024 (Online) 31st January Morning Shift
The ionization energy of sodium in $$\mathrm{~kJ} \mathrm{~mol}^{-1}$$, if electromagnetic radiation of wavelength $$242 \mathrm{~nm}$$ is just suffic...
JEE Main 2024 (Online) 30th January Evening Shift
Number of spectral lines obtained in $$\mathrm{He}^{+}$$ spectra, when an electron makes transition from fifth excited state to first excited state wi...
JEE Main 2024 (Online) 27th January Morning Shift
The number of electrons present in all the completely filled subshells having $$\mathrm{n}=4$$ and $$\mathrm{s}=+\frac{1}{2}$$ is _______. (Where $$\m...
JEE Main 2023 (Online) 15th April Morning Shift
The total number of isoelectronic species from the given set is ___________. $\mathrm{O}^{2-}, \mathrm{F}^{-}, \mathrm{Al}, \mathrm{Mg}^{2+}, \mathrm{...
JEE Main 2023 (Online) 13th April Evening Shift
The orbital angular momentum of an electron in $$3 \mathrm{~s}$$ orbital is $$\frac{x h}{2 \pi}$$. The value of $$x$$ is ____________ (nearest integer...
JEE Main 2023 (Online) 12th April Morning Shift
Values of work function (W$$_0$$) for a few metals are given below .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border...
JEE Main 2023 (Online) 11th April Evening Shift
The number of correct statements from the following is ___________. A. For $$1 \mathrm{s}$$ orbital, the probability density is maximum at the nucleus...
JEE Main 2023 (Online) 10th April Evening Shift
The electron in the $$\mathrm{n}^{\text {th }}$$ orbit of $$\mathrm{Li}^{2+}$$ is excited to $$(\mathrm{n}+1)$$ orbit using the radiation of energy $...
JEE Main 2023 (Online) 10th April Morning Shift
The number of incorrect statement/s about the black body from the following is __________ (A) Emit or absorb energy in the form of electromagnetic rad...
JEE Main 2023 (Online) 8th April Evening Shift
The number of atomic orbitals from the following having 5 radial nodes is ___________. $$7 \mathrm{s}, 7 \mathrm{p}, 6 \mathrm{s}, 8 \mathrm{p}, 8 \ma...
JEE Main 2023 (Online) 8th April Morning Shift
The number of following statement/s which is/are incorrect is ___________ (A) Line emission spectra are used to study the electronic structure (B) The...
JEE Main 2023 (Online) 6th April Morning Shift
The wavelength of an electron of kinetic energy $$4.50\times10^{-29}$$ J is _________ $$\times 10^{-5}$$ m. (Nearest integer) Given : mass of electron...
JEE Main 2023 (Online) 1st February Morning Shift
Electrons in a cathode ray tube have been emitted with a velocity of 1000 m s$$^{-1}$$. The number of following statements which is/are $$\underline {...
JEE Main 2023 (Online) 30th January Morning Shift
The energy of one mole of photons of radiation of frequency $$2 \times 10^{12} \mathrm{~Hz}$$ in $$\mathrm{J} ~\mathrm{mol}^{-1}$$ is ___________. (Ne...
JEE Main 2023 (Online) 29th January Evening Shift
Assume that the radius of the first Bohr orbit of hydrogen atom is 0.6 $$\mathrm{\mathop A\limits^o }$$. The radius of the third Bohr orbit of He$$^+$...
JEE Main 2023 (Online) 25th January Evening Shift
The number of given orbitals which have electron density along the axis is _________ $$\mathrm{p_x,p_y,p_z,d_{xy},d_{yz},d_{xz},d_{z^2},d_{x^2-y^2}}$$...
JEE Main 2023 (Online) 24th January Morning Shift
If wavelength of the first line of the Paschen series of hydrogen atom is 720 nm, then the wavelength of the second line of this series is _________ n...
JEE Main 2022 (Online) 29th July Morning Shift
The minimum uncertainty in the speed of an electron in an one dimensional region of length $$2 \mathrm{a}_{\mathrm{o}}$$ (Where $$\mathrm{a}_{\mathrm{...
JEE Main 2022 (Online) 28th July Evening Shift
If the wavelength for an electron emitted from $$\mathrm{H}$$-atom is $$3.3 \times 10^{-10} \mathrm{~m}$$, then energy absorbed by the electron in its...
JEE Main 2022 (Online) 26th July Evening Shift
Consider an imaginary ion $${ }_{22}^{48} \mathrm{X}^{3-}$$. The nucleus contains '$$a$$'% more neutrons than the number of electrons in the ion. The ...
JEE Main 2022 (Online) 26th July Morning Shift
The wavelength of an electron and a neutron will become equal when the velocity of the electron is $$x$$ times the velocity of neutron. The value of $...
JEE Main 2022 (Online) 25th July Evening Shift
When the excited electron of a H atom from n = 5 drops to the ground state, the maximum number of emission lines observed are _____________.
JEE Main 2022 (Online) 28th June Morning Shift
If the work function of a metal is 6.63 $$\times$$ 10$$-$$19J, the maximum wavelength of the photon required to remove a photoelectron from the metal ...
JEE Main 2022 (Online) 27th June Evening Shift
Consider the following set of quantum numbers. .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border-style:solid;border-...
JEE Main 2022 (Online) 27th June Morning Shift
If the uncertainty in velocity and position of a minute particle in space are, 2.4 $$\times$$ 10$$-$$26 (m s$$-$$1) and 10$$-$$7 (m) respectively. The...
JEE Main 2022 (Online) 25th June Morning Shift
The longest wavelength of light that can be used for the ionisation of lithium atom (Li) in its ground state is x $$\times$$ 10$$-$$8 m. The value of ...
JEE Main 2021 (Online) 1st September Evening Shift
A 50 watt bulb emits monochromatic red light of wavelength of 795 nm. The number of photons emitted per second by the bulb is x $$\times$$ 1020. The v...
JEE Main 2021 (Online) 31st August Morning Shift
Ge(Z = 32) in its ground state electronic configuration has x completely filled orbitals with ml = 0. The value of x is ___________.
JEE Main 2021 (Online) 27th August Evening Shift
The number of photons emitted by a monochromatic (single frequency) infrared range finder of power 1 mW and wavelength of 1000 nm, in 0.1 second is x ...
JEE Main 2021 (Online) 27th August Morning Shift
The kinetic energy of an electron in the second Bohr orbit of a hydrogen atom is equal to $${{{h^2}} \over {xma_0^2}}$$. The value of 10x is _________...
JEE Main 2021 (Online) 26th August Evening Shift
A metal surface is exposed to 500 nm radiation. The threshold frequency of the metal for photoelectric current is 4.3 $$\times$$ 1014 Hz. The velocity...
JEE Main 2021 (Online) 25th July Evening Shift
An accelerated electron has a speed of 5 $$\times$$ 106 ms$$-$$1 with an uncertainty of 0.02%. The uncertainty in finding its location while in motion...
JEE Main 2021 (Online) 25th July Morning Shift
A source of monochromatic radiation of wavelength 400 nm provides 1000 J of energy in 10 seconds. When this radiation falls on the surface of sodium, ...
JEE Main 2021 (Online) 20th July Evening Shift
The wavelength of electrons accelerated from rest through a potential difference of 40 kV is x $$\times$$ 10$$-$$12 m. The value of x is ___________. ...
JEE Main 2021 (Online) 20th July Morning Shift
The Azimuthal quantum number for the valence electrons of Ga+ ion is ___________.(Atomic number of Ga = 31)
JEE Main 2021 (Online) 17th March Morning Shift
A certain orbital has n = 4 and mL = $$-$$3. The number of radial nodes in this orbital is ____________. (Round off to the Nearest Integer)....
JEE Main 2021 (Online) 16th March Evening Shift
The number of orbitals with n = 5, m1 = +2 is ___________. (Round off to the Nearest Integer).
JEE Main 2021 (Online) 16th March Morning Shift
When light of wavelength 248 nm falls on a metal of threshold energy 3.0 eV, the de-Broglie wavelength of emitted electrons is _______$$\mathop A\limi...
JEE Main 2021 (Online) 26th February Evening Shift
A ball weighing 10 g is moving with a velocity of 90 ms$$-$$1. If the uncertainty in its velocity is 5%, then the uncertainty in its position is _____...
JEE Main 2021 (Online) 25th February Evening Shift
Electromagnetic radiation of wavelength 663 nm is just sufficient to ionise the atom of metal A. The ionization enegy of metal A in kJ mol$$-$$1 is __...
JEE Main 2021 (Online) 25th February Evening Shift
Among the following, number of metal/s which can be used as electrodes in the photoelectric cell is _________. (Integer answer)(A) Li(B) Na(C) Rb(D) C...
JEE Main 2021 (Online) 24th February Morning Shift
A proton and a Li3+ nucleus are accelerated by the same potential. If $$\lambda _{Li}$$ and $$\lambda _p$$ denote the de Broglie wavelengths of Li3+ a...
JEE Main 2020 (Online) 2nd September Evening Slot
The work function of sodium metal is 4.41 $$ \times $$ 10–19 J. If photons of wavelength 300 nm are incident on the metal, the kinetic energy of the e...
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