In a hydrogen atom, if energy of an electron in ground state is 13.6. ev, then that in the 2nd excited state is [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 x 10-34 Js) [2002]
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The number of d-electrons retained in Fe2+ [2003] (At. no. of Fe = 26) ion is
The orbital angular momentum for an electron revolving in an orbit is given by This momentum for an s-electron will be given by [2003]
Which one of the following groupings represents a collection of isoelectronic species ?(At. nos. : Cs : 55, Br : 35)[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 electron for Bohr orbits in an atom of hydrogen [2003]
Planck’s constant, h = 6.63 × 10–34 Js
The de Broglie wavelength of a tennis ball of mass 60 g moving with a velocity of 10 metres per second is approximately [2003]
Which of the following sets of quantum numbers is correct for an electron in 4f orbital ? [2004]
Consider the ground state of Cr atom (X = 24). The number of electrons with the azimuthal quantum numbers, ℓ = 1 and 2 are, respectively [2004]
The wavelength of the radiation emitted, when in a hydrogen atom electron falls from infinity to stationary state 1, would be (Rydberg constant = 1.097×107 m–1) [2004]
Which one of the followin g sets of ion s represents the collection of isoelectronic species? [2004]
(Atomic nos. : F = 9, Cl = 17, Na = 11, Mg = 12, Al = 13, K = 19, Ca = 20, Sc = 21)
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 and electric fields? [2005]
(A) n = 1, l = 0, m = 0
(B) n = 2, l = 0, m = 0
(C) n = 2, l = 1, m = 1
(D) n = 3, l = 2, m = 1
(E) n = 3, l = 2, m = 0
Of the following sets which one does NOT contain isoelectronic species? [2005]
According to Bohr's theory, the angular momentum of an electron in 5th orbit is [2006]
Uncertainty in the position of an electron (mass = 9.1 × 10–31 kg) moving with a velocity 300 ms–1, accurate upto 0.001% will be [2006]
(h = 6.63 × 10–34 Js)
Which one of the following sets of ions represents a collection of isoelectronic species? [2006]
Which of the following sets of quantum numbers represents the highest energy of an atom? [2007]
Which one of the following constitutes a group of the isoelectronic species? [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 [2008]
Calculate the wavelength (in nanometer) associated with a proton moving at 1.0 × 103 ms –1. (Mass of proton = 1.67 × 10–27 kg and h = 6.63 × 10–34 Js)
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 located is ( h = 6.6 × 10–34 kg m2s–1, mass of electron, em = 9.1 × 10–31 kg) : [2009]
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 is (c = 3 × 108 ms–1 and NA = 6.02 × 1023 mol–1). [2010]
Ionisation energy of He+ is 19.6 × 10–18 J atom–1. The energy of the first stationary state (n = 1) of Li2+ is [2010]
A gas a bsor bs a ph oton of 355 n m an d emits at two wavelengths. If one of the emissions is at 680 nm, the other is at:[2011]
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 placed in order of increasing energy as : [2012]
Energy of an electron is given by E = – 2.178 ×
Wavelength of light required to excite an electron in an hydrogen atom from level n = 1 to n = 2 will be : (h = 6.62 × 10 –34 Js and c = 3.0 × 108 ms–1) [JEE M 2013]
The correct set of four quantum numbers for the valence electrons of rubidium atom (Z = 37) is: [JEE M 2014]
Which of the following is the energy of a possible excited state of hydrogen ? [JEE M 2015]
A stream of electrons from a heated filaments was passed two charged plates kept at a potential difference V esu. If e and m are charge and mass of an electron, respectively, then the value of h/λ (where λ is wavelength associated with electron wave) is given by: [JEE M 2016]