As per Bohr model, the minimum energy (in eV) required to remove the electron from the ground state of double ionized lithium (Z=3) is

(1) 1.51        (2) 13.6            (3) 40.8        (4) 122.4

Concept Questions :-

Bohr's model of atom
High Yielding Test Series + Question Bank - NEET 2020

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The wavelength of Ka X-rays produced by an X-ray tube is 0.76 $\stackrel{\circ }{A}$. Find the atomic number of the anode material of the tube?

1. 41                                    2. 30

3. 20                                    4. 10

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X-ray
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According to Bohr's theory the moment of momentum of an electron revolving in second orbit of hydrogen atom will be [MP PET 1999; KCET 2003; VITEEE 2006]

(1) 2$\mathrm{\pi h}$        (2) $\mathrm{\pi h}$         (3) $\frac{h}{\mathrm{\pi }}$          (4) $\frac{2h}{\mathrm{\pi }}$

Concept Questions :-

Bohr's model of atom
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The ionisation energy of hydrogen atom is 13.6 eV. Following Bohr's theory, the energy corresponging to a transition between 3rd and 4th orbit is   

(1) 3.40 eV        (2) 1.51 eV        (3) 0.85        (4) 0.66 eV

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Bohr's model of atom
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The K$\propto$ line obtained for molybdenum (Z = 42) target is 0.71 $\stackrel{\circ }{A}$. Then, the wavelength of the ${K}_{\alpha }$ line of copper (Z = 29) is:

(A) 2.14 $\stackrel{\circ }{A}$                               (B) 1.52 $\stackrel{\circ }{A}$

(C) 1.04 $\stackrel{\circ }{A}$                               (D) 0.71 $\stackrel{\circ }{A}$

Concept Questions :-

Spectral series
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The ratio of the energies of the hydrogen atom in its first to second excited states is

(1) $\frac{1}{4}$       (2) $\frac{4}{9}$          (3) $\frac{9}{4}$            (4) 4

Concept Questions :-

Bohr's model of atom
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Energy levels A, B, C of a certain atom correspond to increasing values of energy i.e. ${E}_{A}<{E}_{B}<{E}_{C}.$ If  are the wavelengths of the radiation corresponding to the transitions C to B, B to A and C to A respectively, which of the following relation is correct?

(1) ${\lambda }_{3}={\lambda }_{1}+{\lambda }_{2}$                    (2) ${\lambda }_{3}=\frac{{\lambda }_{1}{\lambda }_{2}}{{\lambda }_{1}+{\lambda }_{2}}$

(3) ${\lambda }_{1}+{\lambda }_{2}+{\lambda }_{3}=0$              (4) ${\lambda }_{3}^{2}={\lambda }_{1}^{2}+{\lambda }_{2}^{2}$

Concept Questions :-

Spectral series
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In the Rutherford scattering experiment, what will be the correct angle for $\propto$-scattering for an impact parameter, b = 0?

(a) ${90}^{\circ }$                                  (b) ${270}^{\circ }$

(c) ${0}^{\circ }$                                    (d) ${180}^{\circ }$

Concept Questions :-

Various atomic model
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The velocity of the electron in the ground state (H - atom) is

(1)              (2)

(3)              (4)

Concept Questions :-

Various atomic model
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When element has a  line whose wavelength is 0.180 nm?

(1) Cobalt             (2) Xenon          (3) Copper             (4) Iron

Concept Questions :-

Spectral series